diff --git a/CHANGELOG.md b/CHANGELOG.md
index 3d7bbd87..b1293c1e 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -5,6 +5,7 @@ HEAD
 ----
 
 * Added implicit conversion from `JsonArray` and `JsonObject` to `JsonVariant`
+* Allow mixed configuration in compilation units (issue #809)
 
 v6.4.0-beta (2018-09-11)
 -----------
diff --git a/src/ArduinoJson.hpp b/src/ArduinoJson.hpp
index 949e6c30..11e8127b 100644
--- a/src/ArduinoJson.hpp
+++ b/src/ArduinoJson.hpp
@@ -4,7 +4,7 @@
 
 #pragma once
 
-#include "ArduinoJson/version.hpp"
+#include "ArduinoJson/Namespace.hpp"
 
 #include "ArduinoJson/DynamicJsonDocument.hpp"
 #include "ArduinoJson/StaticJsonDocument.hpp"
@@ -24,3 +24,16 @@
 #include "ArduinoJson/Json/PrettyJsonSerializer.hpp"
 #include "ArduinoJson/MsgPack/MsgPackDeserializer.hpp"
 #include "ArduinoJson/MsgPack/MsgPackSerializer.hpp"
+
+namespace ArduinoJson {
+using ARDUINOJSON_NAMESPACE::DeserializationError;
+using ARDUINOJSON_NAMESPACE::DynamicJsonDocument;
+using ARDUINOJSON_NAMESPACE::JsonArray;
+using ARDUINOJSON_NAMESPACE::JsonFloat;
+using ARDUINOJSON_NAMESPACE::JsonInteger;
+using ARDUINOJSON_NAMESPACE::JsonObject;
+using ARDUINOJSON_NAMESPACE::JsonUInt;
+using ARDUINOJSON_NAMESPACE::JsonVariant;
+using ARDUINOJSON_NAMESPACE::serialized;
+using ARDUINOJSON_NAMESPACE::StaticJsonDocument;
+}  // namespace ArduinoJson
diff --git a/src/ArduinoJson/Configuration.hpp b/src/ArduinoJson/Configuration.hpp
index af4ea0b5..914dd1de 100644
--- a/src/ArduinoJson/Configuration.hpp
+++ b/src/ArduinoJson/Configuration.hpp
@@ -4,6 +4,18 @@
 
 #pragma once
 
+#if defined(_MSC_VER)
+#define ARDUINOJSON_HAS_INT64 1
+#else
+#define ARDUINOJSON_HAS_INT64 0
+#endif
+
+#if __cplusplus >= 201103L
+#define ARDUINOJSON_HAS_LONG_LONG 1
+#else
+#define ARDUINOJSON_HAS_LONG_LONG 0
+#endif
+
 // Small or big machine?
 #ifndef ARDUINOJSON_EMBEDDED_MODE
 #if defined(ARDUINO) || defined(__IAR_SYSTEMS_ICC__) || defined(__XC) || \
@@ -25,9 +37,6 @@
 #ifndef ARDUINOJSON_USE_LONG_LONG
 #define ARDUINOJSON_USE_LONG_LONG 0
 #endif
-#ifndef ARDUINOJSON_USE_INT64
-#define ARDUINOJSON_USE_INT64 0
-#endif
 
 // Embedded systems usually don't have std::string
 #ifndef ARDUINOJSON_ENABLE_STD_STRING
@@ -53,22 +62,13 @@
 
 // Use long long when available
 #ifndef ARDUINOJSON_USE_LONG_LONG
-#if __cplusplus >= 201103L || (defined(_MSC_VER) && _MSC_VER >= 1800)
+#if ARDUINOJSON_HAS_LONG_LONG || ARDUINOJSON_HAS_INT64
 #define ARDUINOJSON_USE_LONG_LONG 1
 #else
 #define ARDUINOJSON_USE_LONG_LONG 0
 #endif
 #endif
 
-// Use _int64 on old versions of Visual Studio
-#ifndef ARDUINOJSON_USE_INT64
-#if defined(_MSC_VER) && _MSC_VER <= 1700
-#define ARDUINOJSON_USE_INT64 1
-#else
-#define ARDUINOJSON_USE_INT64 0
-#endif
-#endif
-
 // On a computer, we can use std::string
 #ifndef ARDUINOJSON_ENABLE_STD_STRING
 #define ARDUINOJSON_ENABLE_STD_STRING 1
@@ -141,10 +141,6 @@
 #define ARDUINOJSON_NEGATIVE_EXPONENTIATION_THRESHOLD 1e-5
 #endif
 
-#if ARDUINOJSON_USE_LONG_LONG && ARDUINOJSON_USE_INT64
-#error ARDUINOJSON_USE_LONG_LONG and ARDUINOJSON_USE_INT64 cannot be set together
-#endif
-
 #ifndef ARDUINOJSON_LITTLE_ENDIAN
 #if defined(_MSC_VER) ||                                                      \
     (defined(__BYTE_ORDER__) && __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__) || \
diff --git a/src/ArduinoJson/Data/IsVariant.hpp b/src/ArduinoJson/Data/IsVariant.hpp
index 2c543417..ae3659b2 100644
--- a/src/ArduinoJson/Data/IsVariant.hpp
+++ b/src/ArduinoJson/Data/IsVariant.hpp
@@ -6,12 +6,10 @@
 
 #include "../Polyfills/type_traits.hpp"
 
-namespace ArduinoJson {
-namespace Internals {
+namespace ARDUINOJSON_NAMESPACE {
 
 class JsonVariantTag {};
 
 template <typename T>
 struct IsVariant : is_base_of<JsonVariantTag, T> {};
-}  // namespace Internals
-}  // namespace ArduinoJson
+}  // namespace ARDUINOJSON_NAMESPACE
diff --git a/src/ArduinoJson/Data/JsonFloat.hpp b/src/ArduinoJson/Data/JsonFloat.hpp
index 0ed42140..2f6e9570 100644
--- a/src/ArduinoJson/Data/JsonFloat.hpp
+++ b/src/ArduinoJson/Data/JsonFloat.hpp
@@ -6,13 +6,11 @@
 
 #include "../Configuration.hpp"
 
-namespace ArduinoJson {
-namespace Internals {
+namespace ARDUINOJSON_NAMESPACE {
 
 #if ARDUINOJSON_USE_DOUBLE
 typedef double JsonFloat;
 #else
 typedef float JsonFloat;
 #endif
-}
-}
+}  // namespace ARDUINOJSON_NAMESPACE
diff --git a/src/ArduinoJson/Data/JsonInteger.hpp b/src/ArduinoJson/Data/JsonInteger.hpp
index c8ddd00b..650d5854 100644
--- a/src/ArduinoJson/Data/JsonInteger.hpp
+++ b/src/ArduinoJson/Data/JsonInteger.hpp
@@ -6,18 +6,13 @@
 
 #include "../Configuration.hpp"
 
-namespace ArduinoJson {
-namespace Internals {
+namespace ARDUINOJSON_NAMESPACE {
 
 #if ARDUINOJSON_USE_LONG_LONG
-typedef long long JsonInteger;
-typedef unsigned long long JsonUInt;
-#elif ARDUINOJSON_USE_INT64
-typedef __int64 JsonInteger;
-typedef unsigned _int64 JsonUInt;
+typedef int64_t JsonInteger;
+typedef uint64_t JsonUInt;
 #else
 typedef long JsonInteger;
 typedef unsigned long JsonUInt;
 #endif
-}
-}
+}  // namespace ARDUINOJSON_NAMESPACE
diff --git a/src/ArduinoJson/Data/JsonVariantAs.hpp b/src/ArduinoJson/Data/JsonVariantAs.hpp
index a3a08479..34b4a6b2 100644
--- a/src/ArduinoJson/Data/JsonVariantAs.hpp
+++ b/src/ArduinoJson/Data/JsonVariantAs.hpp
@@ -4,8 +4,7 @@
 
 #pragma once
 
-namespace ArduinoJson {
-namespace Internals {
+namespace ARDUINOJSON_NAMESPACE {
 
 // A metafunction that returns the type of the value returned by
 // JsonVariant::as<T>()
@@ -19,5 +18,4 @@ struct JsonVariantAs<char*> {
   typedef const char* type;
 };
 
-}  // namespace Internals
-}  // namespace ArduinoJson
+}  // namespace ARDUINOJSON_NAMESPACE
diff --git a/src/ArduinoJson/Data/JsonVariantContent.hpp b/src/ArduinoJson/Data/JsonVariantContent.hpp
index e7d6e415..63597c76 100644
--- a/src/ArduinoJson/Data/JsonVariantContent.hpp
+++ b/src/ArduinoJson/Data/JsonVariantContent.hpp
@@ -9,8 +9,7 @@
 #include "JsonFloat.hpp"
 #include "JsonInteger.hpp"
 
-namespace ArduinoJson {
-namespace Internals {
+namespace ARDUINOJSON_NAMESPACE {
 struct JsonObjectData {
   struct Slot* head;
   struct Slot* tail;
@@ -40,5 +39,4 @@ union JsonVariantContent {
   } asRaw;
 };
 
-}  // namespace Internals
-}  // namespace ArduinoJson
+}  // namespace ARDUINOJSON_NAMESPACE
diff --git a/src/ArduinoJson/Data/JsonVariantData.hpp b/src/ArduinoJson/Data/JsonVariantData.hpp
index 7a148f62..af9dcabb 100644
--- a/src/ArduinoJson/Data/JsonVariantData.hpp
+++ b/src/ArduinoJson/Data/JsonVariantData.hpp
@@ -7,8 +7,7 @@
 #include "JsonVariantContent.hpp"
 #include "JsonVariantType.hpp"
 
-namespace ArduinoJson {
-namespace Internals {
+namespace ARDUINOJSON_NAMESPACE {
 
 // this struct must be a POD type to prevent error calling offsetof on clang
 struct JsonVariantData {
@@ -31,5 +30,4 @@ inline JsonVariantData *getVariantData(JsonObjectData *obj) {
   return reinterpret_cast<JsonVariantData *>(reinterpret_cast<char *>(obj) -
                                              offset);
 }
-}  // namespace Internals
-}  // namespace ArduinoJson
+}  // namespace ARDUINOJSON_NAMESPACE
diff --git a/src/ArduinoJson/Data/JsonVariantTo.hpp b/src/ArduinoJson/Data/JsonVariantTo.hpp
index cc73dfb6..5b5d4f0a 100644
--- a/src/ArduinoJson/Data/JsonVariantTo.hpp
+++ b/src/ArduinoJson/Data/JsonVariantTo.hpp
@@ -4,13 +4,11 @@
 
 #pragma once
 
-namespace ArduinoJson {
+namespace ARDUINOJSON_NAMESPACE {
 class JsonArray;
 class JsonObject;
 class JsonVariant;
 
-namespace Internals {
-
 // A metafunction that returns the type of the value returned by
 // JsonVariant::to<T>()
 template <typename T>
@@ -29,5 +27,4 @@ struct JsonVariantTo<JsonVariant> {
   typedef JsonVariant type;
 };
 
-}  // namespace Internals
-}  // namespace ArduinoJson
+}  // namespace ARDUINOJSON_NAMESPACE
diff --git a/src/ArduinoJson/Data/JsonVariantType.hpp b/src/ArduinoJson/Data/JsonVariantType.hpp
index 8cf6df50..b83efce0 100644
--- a/src/ArduinoJson/Data/JsonVariantType.hpp
+++ b/src/ArduinoJson/Data/JsonVariantType.hpp
@@ -4,10 +4,7 @@
 
 #pragma once
 
-namespace ArduinoJson {
-
-namespace Internals {
-
+namespace ARDUINOJSON_NAMESPACE {
 // Enumerated type to know the current type of a JsonVariant.
 // The value determines which member of JsonVariantContent is used.
 enum JsonVariantType {
@@ -23,5 +20,4 @@ enum JsonVariantType {
   JSON_OBJECT,
   JSON_FLOAT
 };
-}  // namespace Internals
-}  // namespace ArduinoJson
+}  // namespace ARDUINOJSON_NAMESPACE
diff --git a/src/ArduinoJson/Data/Slot.hpp b/src/ArduinoJson/Data/Slot.hpp
index 72ce7da9..db603b95 100644
--- a/src/ArduinoJson/Data/Slot.hpp
+++ b/src/ArduinoJson/Data/Slot.hpp
@@ -7,8 +7,7 @@
 #include "../Memory/AllocableInMemoryPool.hpp"
 #include "JsonVariantData.hpp"
 
-namespace ArduinoJson {
-namespace Internals {
+namespace ARDUINOJSON_NAMESPACE {
 
 struct Slot : AllocableInMemoryPool {
   JsonVariantData value;
@@ -17,5 +16,4 @@ struct Slot : AllocableInMemoryPool {
   const char* key;
 };
 
-}  // namespace Internals
-}  // namespace ArduinoJson
+}  // namespace ARDUINOJSON_NAMESPACE
diff --git a/src/ArduinoJson/Deserialization/ArduinoStreamReader.hpp b/src/ArduinoJson/Deserialization/ArduinoStreamReader.hpp
index 53260657..9f12ddbe 100644
--- a/src/ArduinoJson/Deserialization/ArduinoStreamReader.hpp
+++ b/src/ArduinoJson/Deserialization/ArduinoStreamReader.hpp
@@ -8,8 +8,7 @@
 
 #include <Stream.h>
 
-namespace ArduinoJson {
-namespace Internals {
+namespace ARDUINOJSON_NAMESPACE {
 
 struct ArduinoStreamReader {
   Stream& _stream;
@@ -35,7 +34,6 @@ struct ArduinoStreamReader {
 inline ArduinoStreamReader makeReader(Stream& input) {
   return ArduinoStreamReader(input);
 }
-}  // namespace Internals
-}  // namespace ArduinoJson
+}  // namespace ARDUINOJSON_NAMESPACE
 
 #endif
diff --git a/src/ArduinoJson/Deserialization/CharPointerReader.hpp b/src/ArduinoJson/Deserialization/CharPointerReader.hpp
index 8414f84a..56a09dfb 100644
--- a/src/ArduinoJson/Deserialization/CharPointerReader.hpp
+++ b/src/ArduinoJson/Deserialization/CharPointerReader.hpp
@@ -4,8 +4,7 @@
 
 #pragma once
 
-namespace ArduinoJson {
-namespace Internals {
+namespace ARDUINOJSON_NAMESPACE {
 
 template <typename TChar>
 class UnsafeCharPointerReader {
@@ -60,5 +59,4 @@ inline SafeCharPointerReader<char> makeReader(const String& input) {
 }
 #endif
 
-}  // namespace Internals
-}  // namespace ArduinoJson
+}  // namespace ARDUINOJSON_NAMESPACE
diff --git a/src/ArduinoJson/Deserialization/DeserializationError.hpp b/src/ArduinoJson/Deserialization/DeserializationError.hpp
index 724f2ab9..92a868b6 100644
--- a/src/ArduinoJson/Deserialization/DeserializationError.hpp
+++ b/src/ArduinoJson/Deserialization/DeserializationError.hpp
@@ -8,7 +8,7 @@
 #include <ostream>
 #endif
 
-namespace ArduinoJson {
+namespace ARDUINOJSON_NAMESPACE {
 
 class DeserializationError {
  public:
@@ -80,4 +80,4 @@ inline std::ostream& operator<<(std::ostream& s, DeserializationError::Code c) {
 }
 #endif
 
-}  // namespace ArduinoJson
+}  // namespace ARDUINOJSON_NAMESPACE
diff --git a/src/ArduinoJson/Deserialization/FlashStringReader.hpp b/src/ArduinoJson/Deserialization/FlashStringReader.hpp
index 2eabf798..e9fd57e6 100644
--- a/src/ArduinoJson/Deserialization/FlashStringReader.hpp
+++ b/src/ArduinoJson/Deserialization/FlashStringReader.hpp
@@ -6,8 +6,7 @@
 
 #if ARDUINOJSON_ENABLE_PROGMEM
 
-namespace ArduinoJson {
-namespace Internals {
+namespace ARDUINOJSON_NAMESPACE {
 class UnsafeFlashStringReader {
   const char* _ptr;
 
@@ -50,7 +49,6 @@ inline SafeFlashStringReader makeReader(const __FlashStringHelper* input,
                                         size_t size) {
   return SafeFlashStringReader(input, size);
 }
-}  // namespace Internals
-}  // namespace ArduinoJson
+}  // namespace ARDUINOJSON_NAMESPACE
 
 #endif
diff --git a/src/ArduinoJson/Deserialization/IteratorReader.hpp b/src/ArduinoJson/Deserialization/IteratorReader.hpp
index 7e01c214..ce33c3a8 100644
--- a/src/ArduinoJson/Deserialization/IteratorReader.hpp
+++ b/src/ArduinoJson/Deserialization/IteratorReader.hpp
@@ -4,8 +4,7 @@
 
 #pragma once
 
-namespace ArduinoJson {
-namespace Internals {
+namespace ARDUINOJSON_NAMESPACE {
 
 template <typename TIterator>
 class IteratorReader {
@@ -30,5 +29,4 @@ inline IteratorReader<typename TInput::const_iterator> makeReader(
   return IteratorReader<typename TInput::const_iterator>(input.begin(),
                                                          input.end());
 }
-}  // namespace Internals
-}  // namespace ArduinoJson
+}  // namespace ARDUINOJSON_NAMESPACE
diff --git a/src/ArduinoJson/Deserialization/StdStreamReader.hpp b/src/ArduinoJson/Deserialization/StdStreamReader.hpp
index 8ad841a7..2db44194 100644
--- a/src/ArduinoJson/Deserialization/StdStreamReader.hpp
+++ b/src/ArduinoJson/Deserialization/StdStreamReader.hpp
@@ -8,8 +8,7 @@
 
 #include <istream>
 
-namespace ArduinoJson {
-namespace Internals {
+namespace ARDUINOJSON_NAMESPACE {
 
 class StdStreamReader {
   std::istream& _stream;
@@ -34,7 +33,6 @@ class StdStreamReader {
 inline StdStreamReader makeReader(std::istream& input) {
   return StdStreamReader(input);
 }
-}  // namespace Internals
-}  // namespace ArduinoJson
+}  // namespace ARDUINOJSON_NAMESPACE
 
 #endif
diff --git a/src/ArduinoJson/Deserialization/deserialize.hpp b/src/ArduinoJson/Deserialization/deserialize.hpp
index a32bbdd3..fedea7f4 100644
--- a/src/ArduinoJson/Deserialization/deserialize.hpp
+++ b/src/ArduinoJson/Deserialization/deserialize.hpp
@@ -12,8 +12,7 @@
 #include "./IteratorReader.hpp"
 #include "./StdStreamReader.hpp"
 
-namespace ArduinoJson {
-namespace Internals {
+namespace ARDUINOJSON_NAMESPACE {
 
 template <template <typename, typename> class TDeserializer,
           typename TMemoryPool, typename TReader, typename TWriter>
@@ -29,10 +28,8 @@ TDeserializer<TReader, TWriter> makeDeserializer(TMemoryPool &memoryPool,
 // TString = const std::string&, const String&
 template <template <typename, typename> class TDeserializer, typename TDocument,
           typename TString>
-typename Internals::enable_if<!Internals::is_array<TString>::value,
-                              DeserializationError>::type
+typename enable_if<!is_array<TString>::value, DeserializationError>::type
 deserialize(TDocument &doc, const TString &input) {
-  using namespace Internals;
   return makeDeserializer<TDeserializer>(
              doc.memoryPool(), makeReader(input),
              makeStringStorage(doc.memoryPool(), input), doc.nestingLimit)
@@ -45,7 +42,6 @@ deserialize(TDocument &doc, const TString &input) {
 template <template <typename, typename> class TDeserializer, typename TDocument,
           typename TChar>
 DeserializationError deserialize(TDocument &doc, TChar *input) {
-  using namespace Internals;
   return makeDeserializer<TDeserializer>(
              doc.memoryPool(), makeReader(input),
              makeStringStorage(doc.memoryPool(), input), doc.nestingLimit)
@@ -60,7 +56,6 @@ template <template <typename, typename> class TDeserializer, typename TDocument,
           typename TChar>
 DeserializationError deserialize(TDocument &doc, TChar *input,
                                  size_t inputSize) {
-  using namespace Internals;
   return makeDeserializer<TDeserializer>(
              doc.memoryPool(), makeReader(input, inputSize),
              makeStringStorage(doc.memoryPool(), input), doc.nestingLimit)
@@ -73,11 +68,9 @@ DeserializationError deserialize(TDocument &doc, TChar *input,
 template <template <typename, typename> class TDeserializer, typename TDocument,
           typename TStream>
 DeserializationError deserialize(TDocument &doc, TStream &input) {
-  using namespace Internals;
   return makeDeserializer<TDeserializer>(
              doc.memoryPool(), makeReader(input),
              makeStringStorage(doc.memoryPool(), input), doc.nestingLimit)
       .parse(doc.template to<JsonVariant>());
 }
-}  // namespace Internals
-}  // namespace ArduinoJson
+}  // namespace ARDUINOJSON_NAMESPACE
diff --git a/src/ArduinoJson/DynamicJsonDocument.hpp b/src/ArduinoJson/DynamicJsonDocument.hpp
index 92547e78..e4e63cf9 100644
--- a/src/ArduinoJson/DynamicJsonDocument.hpp
+++ b/src/ArduinoJson/DynamicJsonDocument.hpp
@@ -8,7 +8,7 @@
 #include "JsonVariant.hpp"
 #include "Memory/DynamicMemoryPool.hpp"
 
-namespace ArduinoJson {
+namespace ARDUINOJSON_NAMESPACE {
 
 class DynamicJsonDocument {
  public:
@@ -25,19 +25,19 @@ class DynamicJsonDocument {
   }
 
   template <typename T>
-  typename Internals::JsonVariantAs<T>::type as() const {
+  typename JsonVariantAs<T>::type as() const {
     return getVariant().as<T>();
   }
 
   template <typename T>
-  typename Internals::JsonVariantTo<T>::type to() {
+  typename JsonVariantTo<T>::type to() {
     _memoryPool.clear();
     return getVariant().to<T>();
   }
 
   void clear() {
     _memoryPool.clear();
-    _rootData.type = Internals::JSON_NULL;
+    _rootData.type = JSON_NULL;
   }
 
   size_t memoryUsage() const {
@@ -49,7 +49,7 @@ class DynamicJsonDocument {
     return getVariant().accept(visitor);
   }
 
-  Internals::DynamicMemoryPool& memoryPool() {
+  DynamicMemoryPool& memoryPool() {
     return _memoryPool;
   }
 
@@ -58,7 +58,7 @@ class DynamicJsonDocument {
     return JsonVariant(&_memoryPool, &_rootData);
   }
 
-  mutable Internals::DynamicMemoryPool _memoryPool;
-  mutable Internals::JsonVariantData _rootData;
+  mutable DynamicMemoryPool _memoryPool;
+  mutable JsonVariantData _rootData;
 };
-}  // namespace ArduinoJson
+}  // namespace ARDUINOJSON_NAMESPACE
diff --git a/src/ArduinoJson/Json/EscapeSequence.hpp b/src/ArduinoJson/Json/EscapeSequence.hpp
index fd3a760c..b2ace9a7 100644
--- a/src/ArduinoJson/Json/EscapeSequence.hpp
+++ b/src/ArduinoJson/Json/EscapeSequence.hpp
@@ -4,8 +4,7 @@
 
 #pragma once
 
-namespace ArduinoJson {
-namespace Internals {
+namespace ARDUINOJSON_NAMESPACE {
 
 class EscapeSequence {
  public:
@@ -33,5 +32,4 @@ class EscapeSequence {
     return &"\"\"\\\\b\bf\fn\nr\rt\t"[excludeIdenticals ? 4 : 0];
   }
 };
-}  // namespace Internals
-}  // namespace ArduinoJson
+}  // namespace ARDUINOJSON_NAMESPACE
diff --git a/src/ArduinoJson/Json/IndentedPrint.hpp b/src/ArduinoJson/Json/IndentedPrint.hpp
index 75d28fc8..68ec5c3a 100644
--- a/src/ArduinoJson/Json/IndentedPrint.hpp
+++ b/src/ArduinoJson/Json/IndentedPrint.hpp
@@ -4,8 +4,7 @@
 
 #pragma once
 
-namespace ArduinoJson {
-namespace Internals {
+namespace ARDUINOJSON_NAMESPACE {
 
 // Decorator on top of Print to allow indented output.
 // This class is used by serializeJsonPretty() but can also be used
@@ -67,5 +66,4 @@ class IndentedPrint {
   static const int MAX_LEVEL = 15;    // because it's only 4 bits
   static const int MAX_TAB_SIZE = 7;  // because it's only 3 bits
 };
-}  // namespace Internals
-}  // namespace ArduinoJson
+}  // namespace ARDUINOJSON_NAMESPACE
diff --git a/src/ArduinoJson/Json/JsonDeserializer.hpp b/src/ArduinoJson/Json/JsonDeserializer.hpp
index e04cf9c8..34c72872 100644
--- a/src/ArduinoJson/Json/JsonDeserializer.hpp
+++ b/src/ArduinoJson/Json/JsonDeserializer.hpp
@@ -12,8 +12,7 @@
 #include "../Polyfills/type_traits.hpp"
 #include "./EscapeSequence.hpp"
 
-namespace ArduinoJson {
-namespace Internals {
+namespace ARDUINOJSON_NAMESPACE {
 
 template <typename TReader, typename TStringStorage>
 class JsonDeserializer {
@@ -339,31 +338,26 @@ class JsonDeserializer {
   uint8_t _nestingLimit;
   char _current;
   bool _loaded;
-};  // namespace Internals
-}  // namespace Internals
+};
 
 template <typename TDocument, typename TInput>
 DeserializationError deserializeJson(TDocument &doc, const TInput &input) {
-  using namespace Internals;
   return deserialize<JsonDeserializer>(doc, input);
 }
 
 template <typename TDocument, typename TInput>
 DeserializationError deserializeJson(TDocument &doc, TInput *input) {
-  using namespace Internals;
   return deserialize<JsonDeserializer>(doc, input);
 }
 
 template <typename TDocument, typename TInput>
 DeserializationError deserializeJson(TDocument &doc, TInput *input,
                                      size_t inputSize) {
-  using namespace Internals;
   return deserialize<JsonDeserializer>(doc, input, inputSize);
 }
 
 template <typename TDocument, typename TInput>
 DeserializationError deserializeJson(TDocument &doc, TInput &input) {
-  using namespace Internals;
   return deserialize<JsonDeserializer>(doc, input);
 }
-}  // namespace ArduinoJson
+}  // namespace ARDUINOJSON_NAMESPACE
diff --git a/src/ArduinoJson/Json/JsonSerializer.hpp b/src/ArduinoJson/Json/JsonSerializer.hpp
index ba808e02..47cc9a82 100644
--- a/src/ArduinoJson/Json/JsonSerializer.hpp
+++ b/src/ArduinoJson/Json/JsonSerializer.hpp
@@ -8,8 +8,7 @@
 #include "../Serialization/serialize.hpp"
 #include "./JsonWriter.hpp"
 
-namespace ArduinoJson {
-namespace Internals {
+namespace ARDUINOJSON_NAMESPACE {
 
 template <typename TWriter>
 class JsonSerializer {
@@ -88,23 +87,18 @@ class JsonSerializer {
   JsonWriter<TWriter> _writer;
 };
 
-}  // namespace Internals
-
 template <typename TSource, typename TDestination>
 size_t serializeJson(const TSource &source, TDestination &destination) {
-  using namespace Internals;
   return serialize<JsonSerializer>(source, destination);
 }
 
 template <typename TSource>
 size_t serializeJson(const TSource &source, char *buffer, size_t bufferSize) {
-  using namespace Internals;
   return serialize<JsonSerializer>(source, buffer, bufferSize);
 }
 
 template <typename TSource>
 size_t measureJson(const TSource &source) {
-  using namespace Internals;
   return measure<JsonSerializer>(source);
 }
 
@@ -122,7 +116,6 @@ inline std::ostream &operator<<(std::ostream &os, const JsonVariant &source) {
   return os;
 }
 
-namespace Internals {
 inline std::ostream &operator<<(std::ostream &os,
                                 const JsonArraySubscript &source) {
   serializeJson(source, os);
@@ -135,8 +128,6 @@ inline std::ostream &operator<<(std::ostream &os,
   serializeJson(source, os);
   return os;
 }
-}  // namespace Internals
-
 #endif
 
-}  // namespace ArduinoJson
+}  // namespace ARDUINOJSON_NAMESPACE
diff --git a/src/ArduinoJson/Json/JsonWriter.hpp b/src/ArduinoJson/Json/JsonWriter.hpp
index 680e7e6c..ecbc5691 100644
--- a/src/ArduinoJson/Json/JsonWriter.hpp
+++ b/src/ArduinoJson/Json/JsonWriter.hpp
@@ -11,8 +11,7 @@
 #include "../Polyfills/attributes.hpp"
 #include "./EscapeSequence.hpp"
 
-namespace ArduinoJson {
-namespace Internals {
+namespace ARDUINOJSON_NAMESPACE {
 
 template <typename TWriter>
 class JsonWriter {
@@ -154,5 +153,4 @@ class JsonWriter {
  private:
   JsonWriter &operator=(const JsonWriter &);  // cannot be assigned
 };
-}  // namespace Internals
-}  // namespace ArduinoJson
+}  // namespace ARDUINOJSON_NAMESPACE
diff --git a/src/ArduinoJson/Json/PrettyJsonSerializer.hpp b/src/ArduinoJson/Json/PrettyJsonSerializer.hpp
index 247ee173..307a81d0 100644
--- a/src/ArduinoJson/Json/PrettyJsonSerializer.hpp
+++ b/src/ArduinoJson/Json/PrettyJsonSerializer.hpp
@@ -10,8 +10,7 @@
 #include "./JsonSerializer.hpp"
 #include "./Prettyfier.hpp"
 
-namespace ArduinoJson {
-namespace Internals {
+namespace ARDUINOJSON_NAMESPACE {
 
 template <typename TPrint>
 class PrettyJsonSerializer_Base {
@@ -33,25 +32,21 @@ class PrettyJsonSerializer : PrettyJsonSerializer_Base<TPrint>,
         JsonSerializer<Prettyfier<TPrint> >(
             PrettyJsonSerializer_Base<TPrint>::_prettyfier) {}
 };
-}  // namespace Internals
 
 template <typename TSource, typename TDestination>
 size_t serializeJsonPretty(TSource &source, TDestination &destination) {
-  using namespace Internals;
   return serialize<PrettyJsonSerializer>(source, destination);
 }
 
 template <typename TSource>
 size_t serializeJsonPretty(const TSource &source, char *buffer,
                            size_t bufferSize) {
-  using namespace Internals;
   return serialize<PrettyJsonSerializer>(source, buffer, bufferSize);
 }
 
 template <typename TSource>
 size_t measureJsonPretty(const TSource &source) {
-  using namespace Internals;
   return measure<PrettyJsonSerializer>(source);
 }
 
-}  // namespace ArduinoJson
+}  // namespace ARDUINOJSON_NAMESPACE
diff --git a/src/ArduinoJson/Json/Prettyfier.hpp b/src/ArduinoJson/Json/Prettyfier.hpp
index 8168875a..4da7ce76 100644
--- a/src/ArduinoJson/Json/Prettyfier.hpp
+++ b/src/ArduinoJson/Json/Prettyfier.hpp
@@ -6,8 +6,7 @@
 
 #include "IndentedPrint.hpp"
 
-namespace ArduinoJson {
-namespace Internals {
+namespace ARDUINOJSON_NAMESPACE {
 
 // Converts a compact JSON string into an indented one.
 template <typename TWriter>
@@ -141,5 +140,4 @@ class Prettyfier {
   IndentedPrint<TWriter>& _sink;
   bool _inString;
 };
-}  // namespace Internals
-}  // namespace ArduinoJson
+}  // namespace ARDUINOJSON_NAMESPACE
diff --git a/src/ArduinoJson/JsonArray.hpp b/src/ArduinoJson/JsonArray.hpp
index 3e03a08f..8d248fb2 100644
--- a/src/ArduinoJson/JsonArray.hpp
+++ b/src/ArduinoJson/JsonArray.hpp
@@ -10,14 +10,12 @@
 // Returns the size (in bytes) of an array with n elements.
 // Can be very handy to determine the size of a StaticMemoryPool.
 #define JSON_ARRAY_SIZE(NUMBER_OF_ELEMENTS) \
-  ((NUMBER_OF_ELEMENTS) * sizeof(ArduinoJson::Internals::Slot))
+  ((NUMBER_OF_ELEMENTS) * sizeof(ARDUINOJSON_NAMESPACE::Slot))
 
-namespace ArduinoJson {
+namespace ARDUINOJSON_NAMESPACE {
 
 class JsonObject;
-namespace Internals {
 class JsonArraySubscript;
-}
 
 class JsonArray {
   friend class JsonVariant;
@@ -26,12 +24,10 @@ class JsonArray {
   typedef JsonArrayIterator iterator;
 
   FORCE_INLINE JsonArray() : _memoryPool(0), _data(0) {}
-  FORCE_INLINE JsonArray(Internals::MemoryPool* pool,
-                         Internals::JsonArrayData* arr)
+  FORCE_INLINE JsonArray(MemoryPool* pool, JsonArrayData* arr)
       : _memoryPool(pool), _data(arr) {}
 
   operator JsonVariant() {
-    using namespace Internals;
     return JsonVariant(_memoryPool, getVariantData(_data));
   }
 
@@ -59,7 +55,7 @@ class JsonArray {
   JsonVariant add() {
     if (!_data) return JsonVariant();
 
-    Internals::Slot* slot = new (_memoryPool) Internals::Slot();
+    Slot* slot = new (_memoryPool) Slot();
     if (!slot) return JsonVariant();
 
     slot->next = 0;
@@ -151,10 +147,9 @@ class JsonArray {
   FORCE_INLINE JsonArray createNestedArray();
   FORCE_INLINE JsonObject createNestedObject();
 
-  FORCE_INLINE Internals::JsonArraySubscript operator[](size_t index);
+  FORCE_INLINE JsonArraySubscript operator[](size_t index);
 
-  FORCE_INLINE const Internals::JsonArraySubscript operator[](
-      size_t index) const;
+  FORCE_INLINE const JsonArraySubscript operator[](size_t index) const;
 
   FORCE_INLINE bool operator==(JsonArray rhs) const {
     iterator it1 = begin();
@@ -171,8 +166,7 @@ class JsonArray {
 
   // Gets the value at the specified index.
   template <typename T>
-  FORCE_INLINE typename Internals::JsonVariantAs<T>::type get(
-      size_t index) const {
+  FORCE_INLINE typename JsonVariantAs<T>::type get(size_t index) const {
     iterator it = begin() += index;
     return it != end() ? it->as<T>() : T();
   }
@@ -188,7 +182,7 @@ class JsonArray {
   FORCE_INLINE void remove(iterator it) {
     if (!_data) return;
 
-    Internals::Slot* slot = it.internal();
+    Slot* slot = it.internal();
     if (!slot) return;
 
     if (slot->prev)
@@ -235,7 +229,7 @@ class JsonArray {
 
   FORCE_INLINE size_t size() const {
     if (!_data) return 0;
-    Internals::Slot* slot = _data->head;
+    Slot* slot = _data->head;
     size_t n = 0;
     while (slot) {
       slot = slot->next;
@@ -269,7 +263,7 @@ class JsonArray {
     return add().set(value);
   }
 
-  Internals::MemoryPool* _memoryPool;
-  Internals::JsonArrayData* _data;
+  MemoryPool* _memoryPool;
+  JsonArrayData* _data;
 };
-}  // namespace ArduinoJson
+}  // namespace ARDUINOJSON_NAMESPACE
diff --git a/src/ArduinoJson/JsonArrayImpl.hpp b/src/ArduinoJson/JsonArrayImpl.hpp
index 11d4ea31..d3da8409 100644
--- a/src/ArduinoJson/JsonArrayImpl.hpp
+++ b/src/ArduinoJson/JsonArrayImpl.hpp
@@ -7,7 +7,7 @@
 #include "JsonArray.hpp"
 #include "JsonObject.hpp"
 
-namespace ArduinoJson {
+namespace ARDUINOJSON_NAMESPACE {
 
 inline JsonArray JsonArray::createNestedArray() {
   return add().to<JsonArray>();
@@ -16,4 +16,4 @@ inline JsonArray JsonArray::createNestedArray() {
 inline JsonObject JsonArray::createNestedObject() {
   return add().to<JsonObject>();
 }
-}  // namespace ArduinoJson
+}  // namespace ARDUINOJSON_NAMESPACE
diff --git a/src/ArduinoJson/JsonArrayIterator.hpp b/src/ArduinoJson/JsonArrayIterator.hpp
index 85c74ee1..5cdfef23 100644
--- a/src/ArduinoJson/JsonArrayIterator.hpp
+++ b/src/ArduinoJson/JsonArrayIterator.hpp
@@ -7,12 +7,11 @@
 #include "Data/Slot.hpp"
 #include "JsonVariant.hpp"
 
-namespace ArduinoJson {
+namespace ARDUINOJSON_NAMESPACE {
 
 class JsonVariantPtr {
  public:
-  JsonVariantPtr(Internals::MemoryPool *memoryPool,
-                 Internals::JsonVariantData *data)
+  JsonVariantPtr(MemoryPool *memoryPool, JsonVariantData *data)
       : _variant(memoryPool, data) {}
 
   JsonVariant *operator->() {
@@ -30,8 +29,7 @@ class JsonVariantPtr {
 class JsonArrayIterator {
  public:
   JsonArrayIterator() : _slot(0) {}
-  explicit JsonArrayIterator(Internals::MemoryPool *memoryPool,
-                             Internals::Slot *iterator)
+  explicit JsonArrayIterator(MemoryPool *memoryPool, Slot *iterator)
       : _memoryPool(memoryPool), _slot(iterator) {}
 
   JsonVariant operator*() const {
@@ -62,12 +60,12 @@ class JsonArrayIterator {
     return *this;
   }
 
-  Internals::Slot *internal() {
+  Slot *internal() {
     return _slot;
   }
 
  private:
-  Internals::MemoryPool *_memoryPool;
-  Internals::Slot *_slot;
+  MemoryPool *_memoryPool;
+  Slot *_slot;
 };
-}  // namespace ArduinoJson
+}  // namespace ARDUINOJSON_NAMESPACE
diff --git a/src/ArduinoJson/JsonArraySubscript.hpp b/src/ArduinoJson/JsonArraySubscript.hpp
index 125f14ca..839e8de7 100644
--- a/src/ArduinoJson/JsonArraySubscript.hpp
+++ b/src/ArduinoJson/JsonArraySubscript.hpp
@@ -12,8 +12,7 @@
 #pragma warning(disable : 4522)
 #endif
 
-namespace ArduinoJson {
-namespace Internals {
+namespace ARDUINOJSON_NAMESPACE {
 class JsonArraySubscript : public JsonVariantBase<JsonArraySubscript> {
  public:
   FORCE_INLINE JsonArraySubscript(JsonArray array, size_t index)
@@ -100,17 +99,15 @@ inline const JsonArraySubscript JsonVariantSubscripts<TImpl>::operator[](
     size_t index) const {
   return impl()->template as<JsonArray>()[index];
 }
-}  // namespace Internals
 
-inline Internals::JsonArraySubscript JsonArray::operator[](size_t index) {
-  return Internals::JsonArraySubscript(*this, index);
+inline JsonArraySubscript JsonArray::operator[](size_t index) {
+  return JsonArraySubscript(*this, index);
 }
 
-inline const Internals::JsonArraySubscript JsonArray::operator[](
-    size_t index) const {
-  return Internals::JsonArraySubscript(*this, index);
+inline const JsonArraySubscript JsonArray::operator[](size_t index) const {
+  return JsonArraySubscript(*this, index);
 }
-}  // namespace ArduinoJson
+}  // namespace ARDUINOJSON_NAMESPACE
 
 #ifdef _MSC_VER
 #pragma warning(pop)
diff --git a/src/ArduinoJson/JsonObject.hpp b/src/ArduinoJson/JsonObject.hpp
index 4e67d699..00d580c5 100644
--- a/src/ArduinoJson/JsonObject.hpp
+++ b/src/ArduinoJson/JsonObject.hpp
@@ -9,9 +9,9 @@
 // Returns the size (in bytes) of an object with n elements.
 // Can be very handy to determine the size of a StaticMemoryPool.
 #define JSON_OBJECT_SIZE(NUMBER_OF_ELEMENTS) \
-  ((NUMBER_OF_ELEMENTS) * sizeof(ArduinoJson::Internals::Slot))
+  ((NUMBER_OF_ELEMENTS) * sizeof(ARDUINOJSON_NAMESPACE::Slot))
 
-namespace ArduinoJson {
+namespace ARDUINOJSON_NAMESPACE {
 
 class JsonObject {
   friend class JsonVariant;
@@ -20,12 +20,10 @@ class JsonObject {
   typedef JsonObjectIterator iterator;
 
   FORCE_INLINE JsonObject() : _memoryPool(0), _data(0) {}
-  FORCE_INLINE JsonObject(Internals::MemoryPool* buf,
-                          Internals::JsonObjectData* object)
+  FORCE_INLINE JsonObject(MemoryPool* buf, JsonObjectData* object)
       : _memoryPool(buf), _data(object) {}
 
   operator JsonVariant() {
-    using namespace Internals;
     return JsonVariant(_memoryPool, getVariantData(_data));
   }
 
@@ -103,7 +101,7 @@ class JsonObject {
   // TValue = bool, char, long, int, short, float, double,
   //          std::string, String, JsonArray, JsonObject
   template <typename TValue, typename TString>
-  FORCE_INLINE typename Internals::JsonVariantAs<TValue>::type get(
+  FORCE_INLINE typename JsonVariantAs<TValue>::type get(
       const TString& key) const {
     return get_impl<const TString&, TValue>(key);
   }
@@ -113,8 +111,7 @@ class JsonObject {
   // TValue = bool, char, long, int, short, float, double,
   //          std::string, String, JsonArray, JsonObject
   template <typename TValue, typename TString>
-  FORCE_INLINE typename Internals::JsonVariantAs<TValue>::type get(
-      TString* key) const {
+  FORCE_INLINE typename JsonVariantAs<TValue>::type get(TString* key) const {
     return get_impl<TString*, TValue>(key);
   }
 
@@ -144,17 +141,16 @@ class JsonObject {
   // JsonObjectSubscript operator[](TKey)
   // TKey = const std::string&, const String&
   template <typename TString>
-  FORCE_INLINE Internals::JsonObjectSubscript<const TString&> operator[](
+  FORCE_INLINE JsonObjectSubscript<const TString&> operator[](
       const TString& key) {
-    return Internals::JsonObjectSubscript<const TString&>(*this, key);
+    return JsonObjectSubscript<const TString&>(*this, key);
   }
   //
   // JsonObjectSubscript operator[](TKey)
   // TKey = char*, const char*, char[], const char[N], const FlashStringHelper*
   template <typename TString>
-  FORCE_INLINE Internals::JsonObjectSubscript<TString*> operator[](
-      TString* key) {
-    return Internals::JsonObjectSubscript<TString*>(*this, key);
+  FORCE_INLINE JsonObjectSubscript<TString*> operator[](TString* key) {
+    return JsonObjectSubscript<TString*>(*this, key);
   }
 
   // Gets the value associated with the specified key.
@@ -162,17 +158,17 @@ class JsonObject {
   // const JsonObjectSubscript operator[](TKey) const;
   // TKey = const std::string&, const String&
   template <typename TString>
-  FORCE_INLINE const Internals::JsonObjectSubscript<const TString&> operator[](
+  FORCE_INLINE const JsonObjectSubscript<const TString&> operator[](
       const TString& key) const {
-    return Internals::JsonObjectSubscript<const TString&>(*this, key);
+    return JsonObjectSubscript<const TString&>(*this, key);
   }
   //
   // const JsonObjectSubscript operator[](TKey) const;
   // TKey = const char*, const char[N], const FlashStringHelper*
   template <typename TString>
-  FORCE_INLINE const Internals::JsonObjectSubscript<TString*> operator[](
+  FORCE_INLINE const JsonObjectSubscript<TString*> operator[](
       TString* key) const {
-    return Internals::JsonObjectSubscript<TString*>(*this, key);
+    return JsonObjectSubscript<TString*>(*this, key);
   }
 
   FORCE_INLINE bool operator==(JsonObject rhs) const {
@@ -185,7 +181,7 @@ class JsonObject {
 
   FORCE_INLINE void remove(iterator it) {
     if (!_data) return;
-    Internals::Slot* slot = it.internal();
+    Slot* slot = it.internal();
     if (!slot) return;
     if (slot->prev)
       slot->prev->next = slot->next;
@@ -262,7 +258,7 @@ class JsonObject {
   FORCE_INLINE size_t size() const {
     if (!_data) return 0;
     size_t n = 0;
-    Internals::Slot* slot = _data->head;
+    Slot* slot = _data->head;
     while (slot) {
       n++;
       slot = slot->next;
@@ -296,38 +292,38 @@ class JsonObject {
 
   // Returns the list node that matches the specified key.
   template <typename TStringRef>
-  Internals::Slot* findSlot(TStringRef key) {
+  Slot* findSlot(TStringRef key) {
     if (!_data) return 0;
-    Internals::Slot* slot = _data->head;
+    Slot* slot = _data->head;
     while (slot) {
-      if (Internals::makeString(key).equals(slot->key)) break;
+      if (makeString(key).equals(slot->key)) break;
       slot = slot->next;
     }
     return slot;
   }
   template <typename TStringRef>
-  FORCE_INLINE Internals::Slot* findSlot(TStringRef key) const {
+  FORCE_INLINE Slot* findSlot(TStringRef key) const {
     return const_cast<JsonObject*>(this)->findSlot<TStringRef>(key);
   }
 
   template <typename TStringRef, typename TValue>
-  FORCE_INLINE typename Internals::JsonVariantAs<TValue>::type get_impl(
+  FORCE_INLINE typename JsonVariantAs<TValue>::type get_impl(
       TStringRef key) const {
-    Internals::Slot* slot = findSlot<TStringRef>(key);
+    Slot* slot = findSlot<TStringRef>(key);
     return slot ? JsonVariant(_memoryPool, &slot->value).as<TValue>()
                 : TValue();
   }
 
   template <typename TStringRef, typename TValue>
   FORCE_INLINE bool is_impl(TStringRef key) const {
-    Internals::Slot* slot = findSlot<TStringRef>(key);
+    Slot* slot = findSlot<TStringRef>(key);
     return slot ? JsonVariant(_memoryPool, &slot->value).is<TValue>() : false;
   }
 
   template <typename TStringRef>
   FORCE_INLINE void remove_impl(TStringRef key) {
     if (!_data) return;
-    Internals::Slot* slot = findSlot<TStringRef>(key);
+    Slot* slot = findSlot<TStringRef>(key);
     if (!slot) return;
     if (slot->prev)
       slot->prev->next = slot->next;
@@ -344,13 +340,13 @@ class JsonObject {
     if (!_data) return JsonVariant();
 
     // ignore null key
-    if (Internals::makeString(key).is_null()) return JsonVariant();
+    if (makeString(key).is_null()) return JsonVariant();
 
     // search a matching key
-    Internals::Slot* slot = findSlot<TStringRef>(key);
+    Slot* slot = findSlot<TStringRef>(key);
     if (!slot) {
       // add the key
-      slot = new (_memoryPool) Internals::Slot();
+      slot = new (_memoryPool) Slot();
       if (!slot) return JsonVariant();
 
       slot->next = 0;
@@ -371,20 +367,20 @@ class JsonObject {
     return JsonVariant(_memoryPool, &slot->value);
   }
 
-  FORCE_INLINE bool set_key(Internals::Slot* slot, const char* key) {
+  FORCE_INLINE bool set_key(Slot* slot, const char* key) {
     slot->key = key;
     return true;
   }
 
   template <typename T>
-  FORCE_INLINE bool set_key(Internals::Slot* slot, const T& key) {
-    const char* dup = Internals::makeString(key).save(_memoryPool);
+  FORCE_INLINE bool set_key(Slot* slot, const T& key) {
+    const char* dup = makeString(key).save(_memoryPool);
     if (!dup) return false;
     slot->key = dup;
     return true;
   }
 
-  mutable Internals::MemoryPool* _memoryPool;
-  mutable Internals::JsonObjectData* _data;
-};  // namespace ArduinoJson
-}  // namespace ArduinoJson
+  mutable MemoryPool* _memoryPool;
+  mutable JsonObjectData* _data;
+};  // namespace ARDUINOJSON_NAMESPACE
+}  // namespace ARDUINOJSON_NAMESPACE
diff --git a/src/ArduinoJson/JsonObjectImpl.hpp b/src/ArduinoJson/JsonObjectImpl.hpp
index e04f674c..61e4fd3f 100644
--- a/src/ArduinoJson/JsonObjectImpl.hpp
+++ b/src/ArduinoJson/JsonObjectImpl.hpp
@@ -7,7 +7,7 @@
 #include "JsonArray.hpp"
 #include "JsonObject.hpp"
 
-namespace ArduinoJson {
+namespace ARDUINOJSON_NAMESPACE {
 
 template <typename TString>
 inline JsonArray JsonObject::createNestedArray(const TString& key) {
@@ -30,4 +30,4 @@ inline JsonObject JsonObject::createNestedObject_impl(TStringRef key) {
   if (!_data) return JsonObject();
   return set(key).template to<JsonObject>();
 }
-}  // namespace ArduinoJson
+}  // namespace ARDUINOJSON_NAMESPACE
diff --git a/src/ArduinoJson/JsonObjectIterator.hpp b/src/ArduinoJson/JsonObjectIterator.hpp
index 15bf0154..37e0a0da 100644
--- a/src/ArduinoJson/JsonObjectIterator.hpp
+++ b/src/ArduinoJson/JsonObjectIterator.hpp
@@ -6,12 +6,11 @@
 
 #include "JsonPair.hpp"
 
-namespace ArduinoJson {
+namespace ARDUINOJSON_NAMESPACE {
 
 class JsonPairPtr {
  public:
-  JsonPairPtr(Internals::MemoryPool *memoryPool, Internals::Slot *slot)
-      : _pair(memoryPool, slot) {}
+  JsonPairPtr(MemoryPool *memoryPool, Slot *slot) : _pair(memoryPool, slot) {}
 
   const JsonPair *operator->() const {
     return &_pair;
@@ -29,8 +28,7 @@ class JsonObjectIterator {
  public:
   JsonObjectIterator() : _slot(0) {}
 
-  explicit JsonObjectIterator(Internals::MemoryPool *memoryPool,
-                              Internals::Slot *slot)
+  explicit JsonObjectIterator(MemoryPool *memoryPool, Slot *slot)
       : _memoryPool(memoryPool), _slot(slot) {}
 
   JsonPair operator*() const {
@@ -61,12 +59,12 @@ class JsonObjectIterator {
     return *this;
   }
 
-  Internals::Slot *internal() {
+  Slot *internal() {
     return _slot;
   }
 
  private:
-  Internals::MemoryPool *_memoryPool;
-  Internals::Slot *_slot;
+  MemoryPool *_memoryPool;
+  Slot *_slot;
 };
-}  // namespace ArduinoJson
+}  // namespace ARDUINOJSON_NAMESPACE
diff --git a/src/ArduinoJson/JsonObjectSubscript.hpp b/src/ArduinoJson/JsonObjectSubscript.hpp
index 088a021c..b902cf93 100644
--- a/src/ArduinoJson/JsonObjectSubscript.hpp
+++ b/src/ArduinoJson/JsonObjectSubscript.hpp
@@ -13,8 +13,7 @@
 #pragma warning(disable : 4522)
 #endif
 
-namespace ArduinoJson {
-namespace Internals {
+namespace ARDUINOJSON_NAMESPACE {
 
 template <typename TStringRef>
 class JsonObjectSubscript
@@ -130,8 +129,7 @@ inline typename enable_if<IsString<TString *>::value,
   return impl()->template as<JsonObject>()[key];
 }
 
-}  // namespace Internals
-}  // namespace ArduinoJson
+}  // namespace ARDUINOJSON_NAMESPACE
 
 #ifdef _MSC_VER
 #pragma warning(pop)
diff --git a/src/ArduinoJson/JsonPair.hpp b/src/ArduinoJson/JsonPair.hpp
index 9e85c81b..644d4d11 100644
--- a/src/ArduinoJson/JsonPair.hpp
+++ b/src/ArduinoJson/JsonPair.hpp
@@ -6,12 +6,12 @@
 
 #include "JsonVariant.hpp"
 
-namespace ArduinoJson {
+namespace ARDUINOJSON_NAMESPACE {
 
 // A key value pair for JsonObjectData.
 class JsonPair {
  public:
-  JsonPair(Internals::MemoryPool* memoryPool, Internals::Slot* slot) {
+  JsonPair(MemoryPool* memoryPool, Slot* slot) {
     if (slot) {
       _key = slot->key;
       _value = JsonVariant(memoryPool, &slot->value);
@@ -32,4 +32,4 @@ class JsonPair {
   const char* _key;
   JsonVariant _value;
 };
-}  // namespace ArduinoJson
+}  // namespace ARDUINOJSON_NAMESPACE
diff --git a/src/ArduinoJson/JsonVariant.hpp b/src/ArduinoJson/JsonVariant.hpp
index 7b28f37c..7800ccae 100644
--- a/src/ArduinoJson/JsonVariant.hpp
+++ b/src/ArduinoJson/JsonVariant.hpp
@@ -17,7 +17,7 @@
 #include "Serialization/DynamicStringWriter.hpp"
 #include "SerializedValue.hpp"
 
-namespace ArduinoJson {
+namespace ARDUINOJSON_NAMESPACE {
 
 // Forward declarations.
 class JsonArray;
@@ -30,11 +30,10 @@ class JsonObject;
 // - a char, short, int or a long (signed or unsigned)
 // - a string (const char*)
 // - a reference to a JsonArray or JsonObject
-class JsonVariant : public Internals::JsonVariantBase<JsonVariant> {
+class JsonVariant : public JsonVariantBase<JsonVariant> {
  public:
   // Intenal use only
-  FORCE_INLINE JsonVariant(Internals::MemoryPool *memoryPool,
-                           Internals::JsonVariantData *data)
+  FORCE_INLINE JsonVariant(MemoryPool *memoryPool, JsonVariantData *data)
       : _memoryPool(memoryPool), _data(data) {}
 
   // Creates an uninitialized JsonVariant
@@ -43,8 +42,8 @@ class JsonVariant : public Internals::JsonVariantBase<JsonVariant> {
   // set(bool value)
   FORCE_INLINE bool set(bool value) {
     if (!_data) return false;
-    _data->type = Internals::JSON_BOOLEAN;
-    _data->content.asInteger = static_cast<Internals::JsonUInt>(value);
+    _data->type = JSON_BOOLEAN;
+    _data->content.asInteger = static_cast<JsonUInt>(value);
     return true;
   }
 
@@ -52,11 +51,10 @@ class JsonVariant : public Internals::JsonVariantBase<JsonVariant> {
   // set(float value);
   template <typename T>
   FORCE_INLINE bool set(
-      T value, typename Internals::enable_if<
-                   Internals::is_floating_point<T>::value>::type * = 0) {
+      T value, typename enable_if<is_floating_point<T>::value>::type * = 0) {
     if (!_data) return false;
-    _data->type = Internals::JSON_FLOAT;
-    _data->content.asFloat = static_cast<Internals::JsonFloat>(value);
+    _data->type = JSON_FLOAT;
+    _data->content.asFloat = static_cast<JsonFloat>(value);
     return true;
   }
 
@@ -66,18 +64,16 @@ class JsonVariant : public Internals::JsonVariantBase<JsonVariant> {
   // set(signed long)
   // set(signed char)
   template <typename T>
-  FORCE_INLINE bool set(
-      T value,
-      typename Internals::enable_if<Internals::is_integral<T>::value &&
-                                    Internals::is_signed<T>::value>::type * =
-          0) {
+  FORCE_INLINE bool set(T value,
+                        typename enable_if<is_integral<T>::value &&
+                                           is_signed<T>::value>::type * = 0) {
     if (!_data) return false;
     if (value >= 0) {
-      _data->type = Internals::JSON_POSITIVE_INTEGER;
-      _data->content.asInteger = static_cast<Internals::JsonUInt>(value);
+      _data->type = JSON_POSITIVE_INTEGER;
+      _data->content.asInteger = static_cast<JsonUInt>(value);
     } else {
-      _data->type = Internals::JSON_NEGATIVE_INTEGER;
-      _data->content.asInteger = ~static_cast<Internals::JsonUInt>(value) + 1;
+      _data->type = JSON_NEGATIVE_INTEGER;
+      _data->content.asInteger = ~static_cast<JsonUInt>(value) + 1;
     }
     return true;
   }
@@ -86,21 +82,19 @@ class JsonVariant : public Internals::JsonVariantBase<JsonVariant> {
   // set(unsigned int)
   // set(unsigned long)
   template <typename T>
-  FORCE_INLINE bool set(
-      T value,
-      typename Internals::enable_if<Internals::is_integral<T>::value &&
-                                    Internals::is_unsigned<T>::value>::type * =
-          0) {
+  FORCE_INLINE bool set(T value,
+                        typename enable_if<is_integral<T>::value &&
+                                           is_unsigned<T>::value>::type * = 0) {
     if (!_data) return false;
-    _data->type = Internals::JSON_POSITIVE_INTEGER;
-    _data->content.asInteger = static_cast<Internals::JsonUInt>(value);
+    _data->type = JSON_POSITIVE_INTEGER;
+    _data->content.asInteger = static_cast<JsonUInt>(value);
     return true;
   }
 
   // set(SerializedValue<const char *>)
-  FORCE_INLINE bool set(Internals::SerializedValue<const char *> value) {
+  FORCE_INLINE bool set(SerializedValue<const char *> value) {
     if (!_data) return false;
-    _data->type = Internals::JSON_LINKED_RAW;
+    _data->type = JSON_LINKED_RAW;
     _data->content.asRaw.data = value.data();
     _data->content.asRaw.size = value.size();
     return true;
@@ -111,19 +105,17 @@ class JsonVariant : public Internals::JsonVariantBase<JsonVariant> {
   // set(SerializedValue<const __FlashStringHelper*>)
   template <typename T>
   FORCE_INLINE bool set(
-      Internals::SerializedValue<T> value,
-      typename Internals::enable_if<
-          !Internals::is_same<const char *, T>::value>::type * = 0) {
+      SerializedValue<T> value,
+      typename enable_if<!is_same<const char *, T>::value>::type * = 0) {
     if (!_data) return false;
-    const char *dup =
-        Internals::makeString(value.data(), value.size()).save(_memoryPool);
+    const char *dup = makeString(value.data(), value.size()).save(_memoryPool);
     if (dup) {
-      _data->type = Internals::JSON_OWNED_RAW;
+      _data->type = JSON_OWNED_RAW;
       _data->content.asRaw.data = dup;
       _data->content.asRaw.size = value.size();
       return true;
     } else {
-      _data->type = Internals::JSON_NULL;
+      _data->type = JSON_NULL;
       return false;
     }
   }
@@ -131,36 +123,32 @@ class JsonVariant : public Internals::JsonVariantBase<JsonVariant> {
   // set(const std::string&)
   // set(const String&)
   template <typename T>
-  FORCE_INLINE bool set(
-      const T &value,
-      typename Internals::enable_if<Internals::IsString<T>::value>::type * =
-          0) {
+  FORCE_INLINE bool set(const T &value,
+                        typename enable_if<IsString<T>::value>::type * = 0) {
     if (!_data) return false;
-    const char *dup = Internals::makeString(value).save(_memoryPool);
+    const char *dup = makeString(value).save(_memoryPool);
     if (dup) {
-      _data->type = Internals::JSON_OWNED_STRING;
+      _data->type = JSON_OWNED_STRING;
       _data->content.asString = dup;
       return true;
     } else {
-      _data->type = Internals::JSON_NULL;
+      _data->type = JSON_NULL;
       return false;
     }
   }
 
   // set(char*)
   template <typename T>
-  FORCE_INLINE bool set(
-      T *value,
-      typename Internals::enable_if<Internals::IsString<T *>::value>::type * =
-          0) {
+  FORCE_INLINE bool set(T *value,
+                        typename enable_if<IsString<T *>::value>::type * = 0) {
     if (!_data) return false;
-    const char *dup = Internals::makeString(value).save(_memoryPool);
+    const char *dup = makeString(value).save(_memoryPool);
     if (dup) {
-      _data->type = Internals::JSON_OWNED_STRING;
+      _data->type = JSON_OWNED_STRING;
       _data->content.asString = dup;
       return true;
     } else {
-      _data->type = Internals::JSON_NULL;
+      _data->type = JSON_NULL;
       return false;
     }
   }
@@ -168,7 +156,7 @@ class JsonVariant : public Internals::JsonVariantBase<JsonVariant> {
   // set(const char*);
   FORCE_INLINE bool set(const char *value) {
     if (!_data) return false;
-    _data->type = Internals::JSON_LINKED_STRING;
+    _data->type = JSON_LINKED_STRING;
     _data->content.asString = value;
     return true;
   }
@@ -176,10 +164,10 @@ class JsonVariant : public Internals::JsonVariantBase<JsonVariant> {
   bool set(const JsonVariant &value);
 
   FORCE_INLINE bool set(JsonArray array);
-  FORCE_INLINE bool set(const Internals::JsonArraySubscript &);
+  FORCE_INLINE bool set(const JsonArraySubscript &);
   FORCE_INLINE bool set(JsonObject object);
   template <typename TString>
-  FORCE_INLINE bool set(const Internals::JsonObjectSubscript<TString> &);
+  FORCE_INLINE bool set(const JsonObjectSubscript<TString> &);
 
   // Get the variant as the specified type.
   //
@@ -193,20 +181,19 @@ class JsonVariant : public Internals::JsonVariantBase<JsonVariant> {
   // unsigned int as<unsigned int>() const;
   // unsigned long as<unsigned long>() const;
   template <typename T>
-  FORCE_INLINE const typename Internals::enable_if<
-      Internals::is_integral<T>::value, T>::type
-  as() const {
+  FORCE_INLINE const typename enable_if<is_integral<T>::value, T>::type as()
+      const {
     if (!_data) return 0;
     switch (_data->type) {
-      case Internals::JSON_POSITIVE_INTEGER:
-      case Internals::JSON_BOOLEAN:
+      case JSON_POSITIVE_INTEGER:
+      case JSON_BOOLEAN:
         return T(_data->content.asInteger);
-      case Internals::JSON_NEGATIVE_INTEGER:
+      case JSON_NEGATIVE_INTEGER:
         return T(~_data->content.asInteger + 1);
-      case Internals::JSON_LINKED_STRING:
-      case Internals::JSON_OWNED_STRING:
-        return Internals::parseInteger<T>(_data->content.asString);
-      case Internals::JSON_FLOAT:
+      case JSON_LINKED_STRING:
+      case JSON_OWNED_STRING:
+        return parseInteger<T>(_data->content.asString);
+      case JSON_FLOAT:
         return T(_data->content.asFloat);
       default:
         return 0;
@@ -214,29 +201,27 @@ class JsonVariant : public Internals::JsonVariantBase<JsonVariant> {
   }
   // bool as<bool>() const
   template <typename T>
-  FORCE_INLINE const typename Internals::enable_if<
-      Internals::is_same<T, bool>::value, T>::type
-  as() const {
+  FORCE_INLINE const typename enable_if<is_same<T, bool>::value, T>::type as()
+      const {
     return as<int>() != 0;
   }
   //
   // double as<double>() const;
   // float as<float>() const;
   template <typename T>
-  FORCE_INLINE const typename Internals::enable_if<
-      Internals::is_floating_point<T>::value, T>::type
+  FORCE_INLINE const typename enable_if<is_floating_point<T>::value, T>::type
   as() const {
     if (!_data) return 0;
     switch (_data->type) {
-      case Internals::JSON_POSITIVE_INTEGER:
-      case Internals::JSON_BOOLEAN:
+      case JSON_POSITIVE_INTEGER:
+      case JSON_BOOLEAN:
         return static_cast<T>(_data->content.asInteger);
-      case Internals::JSON_NEGATIVE_INTEGER:
+      case JSON_NEGATIVE_INTEGER:
         return -static_cast<T>(_data->content.asInteger);
-      case Internals::JSON_LINKED_STRING:
-      case Internals::JSON_OWNED_STRING:
-        return Internals::parseFloat<T>(_data->content.asString);
-      case Internals::JSON_FLOAT:
+      case JSON_LINKED_STRING:
+      case JSON_OWNED_STRING:
+        return parseFloat<T>(_data->content.asString);
+      case JSON_FLOAT:
         return static_cast<T>(_data->content.asFloat);
       default:
         return 0;
@@ -246,14 +231,13 @@ class JsonVariant : public Internals::JsonVariantBase<JsonVariant> {
   // const char* as<const char*>() const;
   // const char* as<char*>() const;
   template <typename T>
-  FORCE_INLINE typename Internals::enable_if<
-      Internals::is_same<T, const char *>::value ||
-          Internals::is_same<T, char *>::value,
-      const char *>::type
+  FORCE_INLINE typename enable_if<is_same<T, const char *>::value ||
+                                      is_same<T, char *>::value,
+                                  const char *>::type
   as() const {
     if (!_data) return 0;
-    if (_data && (_data->type == Internals::JSON_LINKED_STRING ||
-                  _data->type == Internals::JSON_OWNED_STRING))
+    if (_data &&
+        (_data->type == JSON_LINKED_STRING || _data->type == JSON_OWNED_STRING))
       return _data->content.asString;
     else
       return 0;
@@ -262,10 +246,8 @@ class JsonVariant : public Internals::JsonVariantBase<JsonVariant> {
   // std::string as<std::string>() const;
   // String as<String>() const;
   template <typename T>
-  FORCE_INLINE
-      typename Internals::enable_if<Internals::IsWriteableString<T>::value,
-                                    T>::type
-      as() const {
+  FORCE_INLINE typename enable_if<IsWriteableString<T>::value, T>::type as()
+      const {
     const char *cstr = as<const char *>();
     if (cstr) return T(cstr);
     T s;
@@ -276,27 +258,22 @@ class JsonVariant : public Internals::JsonVariantBase<JsonVariant> {
   // JsonArray as<JsonArray>() const;
   // const JsonArray as<const JsonArray>() const;
   template <typename T>
-  FORCE_INLINE typename Internals::enable_if<
-      Internals::is_same<typename Internals::remove_const<T>::type,
-                         JsonArray>::value,
+  FORCE_INLINE typename enable_if<
+      is_same<typename remove_const<T>::type, JsonArray>::value,
       JsonArray>::type
   as() const;
   //
   // JsonObject as<JsonObject>() const;
   // const JsonObject as<const JsonObject>() const;
   template <typename T>
-  FORCE_INLINE typename Internals::enable_if<
-      Internals::is_same<typename Internals::remove_const<T>::type,
-                         JsonObject>::value,
-      T>::type
+  FORCE_INLINE typename enable_if<
+      is_same<typename remove_const<T>::type, JsonObject>::value, T>::type
   as() const;
   //
   // JsonVariant as<JsonVariant> const;
   template <typename T>
-  FORCE_INLINE
-      typename Internals::enable_if<Internals::is_same<T, JsonVariant>::value,
-                                    T>::type
-      as() const {
+  FORCE_INLINE typename enable_if<is_same<T, JsonVariant>::value, T>::type as()
+      const {
     return *this;
   }
 
@@ -313,69 +290,59 @@ class JsonVariant : public Internals::JsonVariantBase<JsonVariant> {
   // bool is<unsigned int>() const;
   // bool is<unsigned long>() const;
   template <typename T>
-  FORCE_INLINE typename Internals::enable_if<Internals::is_integral<T>::value,
-                                             bool>::type
-  is() const {
-    return _data && (_data->type == Internals::JSON_POSITIVE_INTEGER ||
-                     _data->type == Internals::JSON_NEGATIVE_INTEGER);
+  FORCE_INLINE typename enable_if<is_integral<T>::value, bool>::type is()
+      const {
+    return _data && (_data->type == JSON_POSITIVE_INTEGER ||
+                     _data->type == JSON_NEGATIVE_INTEGER);
   }
   //
   // bool is<double>() const;
   // bool is<float>() const;
   template <typename T>
-  FORCE_INLINE
-      typename Internals::enable_if<Internals::is_floating_point<T>::value,
-                                    bool>::type
-      is() const {
-    return _data && (_data->type == Internals::JSON_FLOAT ||
-                     _data->type == Internals::JSON_POSITIVE_INTEGER ||
-                     _data->type == Internals::JSON_NEGATIVE_INTEGER);
+  FORCE_INLINE typename enable_if<is_floating_point<T>::value, bool>::type is()
+      const {
+    return _data &&
+           (_data->type == JSON_FLOAT || _data->type == JSON_POSITIVE_INTEGER ||
+            _data->type == JSON_NEGATIVE_INTEGER);
   }
   //
   // bool is<bool>() const
   template <typename T>
-  FORCE_INLINE typename Internals::enable_if<Internals::is_same<T, bool>::value,
-                                             bool>::type
-  is() const {
-    return _data && _data->type == Internals::JSON_BOOLEAN;
+  FORCE_INLINE typename enable_if<is_same<T, bool>::value, bool>::type is()
+      const {
+    return _data && _data->type == JSON_BOOLEAN;
   }
   //
   // bool is<const char*>() const;
   // bool is<char*>() const;
   template <typename T>
-  FORCE_INLINE typename Internals::enable_if<
-      Internals::is_same<T, const char *>::value ||
-          Internals::is_same<T, char *>::value,
-      bool>::type
+  FORCE_INLINE typename enable_if<
+      is_same<T, const char *>::value || is_same<T, char *>::value, bool>::type
   is() const {
-    return _data && (_data->type == Internals::JSON_LINKED_STRING ||
-                     _data->type == Internals::JSON_OWNED_STRING);
+    return _data && (_data->type == JSON_LINKED_STRING ||
+                     _data->type == JSON_OWNED_STRING);
   }
   //
   // bool is<JsonArray> const;
   // bool is<const JsonArray> const;
   template <typename T>
-  FORCE_INLINE typename Internals::enable_if<
-      Internals::is_same<typename Internals::remove_const<T>::type,
-                         JsonArray>::value,
-      bool>::type
+  FORCE_INLINE typename enable_if<
+      is_same<typename remove_const<T>::type, JsonArray>::value, bool>::type
   is() const {
-    return _data && _data->type == Internals::JSON_ARRAY;
+    return _data && _data->type == JSON_ARRAY;
   }
   //
   // bool is<JsonObject> const;
   // bool is<const JsonObject> const;
   template <typename T>
-  FORCE_INLINE typename Internals::enable_if<
-      Internals::is_same<typename Internals::remove_const<T>::type,
-                         JsonObject>::value,
-      bool>::type
+  FORCE_INLINE typename enable_if<
+      is_same<typename remove_const<T>::type, JsonObject>::value, bool>::type
   is() const {
-    return _data && _data->type == Internals::JSON_OBJECT;
+    return _data && _data->type == JSON_OBJECT;
   }
 
   FORCE_INLINE bool isNull() const {
-    return _data == 0 || _data->type == Internals::JSON_NULL;
+    return _data == 0 || _data->type == JSON_NULL;
   }
 
   FORCE_INLINE bool isInvalid() const {
@@ -389,35 +356,29 @@ class JsonVariant : public Internals::JsonVariantBase<JsonVariant> {
   //
   // JsonArray to<JsonArray>()
   template <typename T>
-  typename Internals::enable_if<Internals::is_same<T, JsonArray>::value,
-                                JsonArray>::type
-  to();
+  typename enable_if<is_same<T, JsonArray>::value, JsonArray>::type to();
   //
   // JsonObject to<JsonObject>()
   template <typename T>
-  typename Internals::enable_if<Internals::is_same<T, JsonObject>::value,
-                                JsonObject>::type
-  to();
+  typename enable_if<is_same<T, JsonObject>::value, JsonObject>::type to();
   //
   // JsonObject to<JsonVariant>()
   template <typename T>
-  typename Internals::enable_if<Internals::is_same<T, JsonVariant>::value,
-                                JsonVariant>::type
-  to();
+  typename enable_if<is_same<T, JsonVariant>::value, JsonVariant>::type to();
 
  private:
-  Internals::MemoryPool *_memoryPool;
-  Internals::JsonVariantData *_data;
+  MemoryPool *_memoryPool;
+  JsonVariantData *_data;
 };
 
 class JsonVariantLocal : public JsonVariant {
  public:
-  explicit JsonVariantLocal(Internals::MemoryPool *memoryPool)
+  explicit JsonVariantLocal(MemoryPool *memoryPool)
       : JsonVariant(memoryPool, &_localData) {
-    _localData.type = Internals::JSON_NULL;
+    _localData.type = JSON_NULL;
   }
 
  private:
-  Internals::JsonVariantData _localData;
+  JsonVariantData _localData;
 };
-}  // namespace ArduinoJson
+}  // namespace ARDUINOJSON_NAMESPACE
diff --git a/src/ArduinoJson/JsonVariantBase.hpp b/src/ArduinoJson/JsonVariantBase.hpp
index 268326ca..478be4df 100644
--- a/src/ArduinoJson/JsonVariantBase.hpp
+++ b/src/ArduinoJson/JsonVariantBase.hpp
@@ -9,8 +9,7 @@
 #include "JsonVariantOr.hpp"
 #include "JsonVariantSubscripts.hpp"
 
-namespace ArduinoJson {
-namespace Internals {
+namespace ARDUINOJSON_NAMESPACE {
 
 template <typename TImpl>
 class JsonVariantBase : public JsonVariantCasts<TImpl>,
@@ -18,5 +17,4 @@ class JsonVariantBase : public JsonVariantCasts<TImpl>,
                         public JsonVariantOr<TImpl>,
                         public JsonVariantSubscripts<TImpl>,
                         public JsonVariantTag {};
-}  // namespace Internals
-}  // namespace ArduinoJson
+}  // namespace ARDUINOJSON_NAMESPACE
diff --git a/src/ArduinoJson/JsonVariantCasts.hpp b/src/ArduinoJson/JsonVariantCasts.hpp
index ae3c1c14..04d64d37 100644
--- a/src/ArduinoJson/JsonVariantCasts.hpp
+++ b/src/ArduinoJson/JsonVariantCasts.hpp
@@ -7,8 +7,7 @@
 #include "Data/JsonVariantAs.hpp"
 #include "Polyfills/attributes.hpp"
 
-namespace ArduinoJson {
-namespace Internals {
+namespace ARDUINOJSON_NAMESPACE {
 
 template <typename TImpl>
 class JsonVariantCasts {
@@ -23,5 +22,4 @@ class JsonVariantCasts {
     return static_cast<const TImpl *>(this);
   }
 };
-}  // namespace Internals
-}  // namespace ArduinoJson
+}  // namespace ARDUINOJSON_NAMESPACE
diff --git a/src/ArduinoJson/JsonVariantComparisons.hpp b/src/ArduinoJson/JsonVariantComparisons.hpp
index c9c6c5e8..d8b0cdaf 100644
--- a/src/ArduinoJson/JsonVariantComparisons.hpp
+++ b/src/ArduinoJson/JsonVariantComparisons.hpp
@@ -10,12 +10,10 @@
 #include "Polyfills/type_traits.hpp"
 #include "Strings/StringTypes.hpp"
 
-namespace ArduinoJson {
+namespace ARDUINOJSON_NAMESPACE {
 class JsonArray;
 class JsonObject;
 
-namespace Internals {
-
 template <typename TImpl>
 class JsonVariantComparisons {
  public:
@@ -120,7 +118,6 @@ class JsonVariantComparisons {
 
   template <typename TVariant2>
   bool equals(const JsonVariantComparisons<TVariant2> &right) const {
-    using namespace Internals;
     if (is<bool>() && right.template is<bool>())
       return as<bool>() == right.template as<bool>();
     if (is<JsonInteger>() && right.template is<JsonInteger>())
@@ -137,5 +134,4 @@ class JsonVariantComparisons {
     return false;
   }
 };
-}  // namespace Internals
-}  // namespace ArduinoJson
+}  // namespace ARDUINOJSON_NAMESPACE
diff --git a/src/ArduinoJson/JsonVariantImpl.hpp b/src/ArduinoJson/JsonVariantImpl.hpp
index d6322dbf..d4d41904 100644
--- a/src/ArduinoJson/JsonVariantImpl.hpp
+++ b/src/ArduinoJson/JsonVariantImpl.hpp
@@ -11,13 +11,13 @@
 
 #include <string.h>  // for strcmp
 
-namespace ArduinoJson {
+namespace ARDUINOJSON_NAMESPACE {
 
 inline bool JsonVariant::set(JsonArray array) {
   return to<JsonArray>().copyFrom(array);
 }
 
-inline bool JsonVariant::set(const Internals::JsonArraySubscript& value) {
+inline bool JsonVariant::set(const JsonArraySubscript& value) {
   return set(value.as<JsonVariant>());
 }
 
@@ -26,25 +26,24 @@ inline bool JsonVariant::set(JsonObject object) {
 }
 
 template <typename TString>
-inline bool JsonVariant::set(
-    const Internals::JsonObjectSubscript<TString>& value) {
+inline bool JsonVariant::set(const JsonObjectSubscript<TString>& value) {
   return set(value.template as<JsonVariant>());
 }
 
 inline bool JsonVariant::set(const JsonVariant& value) {
   if (!_data) return false;
   if (!value._data) {
-    _data->type = Internals::JSON_NULL;
+    _data->type = JSON_NULL;
     return true;
   }
   switch (value._data->type) {
-    case Internals::JSON_ARRAY:
+    case JSON_ARRAY:
       return set(value.as<JsonArray>());
-    case Internals::JSON_OBJECT:
+    case JSON_OBJECT:
       return set(value.as<JsonObject>());
-    case Internals::JSON_OWNED_STRING:
+    case JSON_OWNED_STRING:
       return set(const_cast<char*>(value._data->content.asString));
-    case Internals::JSON_OWNED_RAW:
+    case JSON_OWNED_RAW:
       return set(serialized(const_cast<char*>(value._data->content.asRaw.data),
                             value._data->content.asRaw.size));
     default:
@@ -54,63 +53,55 @@ inline bool JsonVariant::set(const JsonVariant& value) {
 }
 
 template <typename T>
-inline typename Internals::enable_if<
-    Internals::is_same<typename Internals::remove_const<T>::type,
-                       JsonArray>::value,
-    JsonArray>::type
+inline typename enable_if<
+    is_same<typename remove_const<T>::type, JsonArray>::value, JsonArray>::type
 JsonVariant::as() const {
-  if (_data && _data->type == Internals::JSON_ARRAY)
+  if (_data && _data->type == JSON_ARRAY)
     return JsonArray(_memoryPool, &_data->content.asArray);
   else
     return JsonArray();
 }
 
 template <typename T>
-inline typename Internals::enable_if<
-    Internals::is_same<typename Internals::remove_const<T>::type,
-                       JsonObject>::value,
-    T>::type
+inline typename enable_if<
+    is_same<typename remove_const<T>::type, JsonObject>::value, T>::type
 JsonVariant::as() const {
-  if (_data && _data->type == Internals::JSON_OBJECT)
+  if (_data && _data->type == JSON_OBJECT)
     return JsonObject(_memoryPool, &_data->content.asObject);
   else
     return JsonObject();
 }
 
 template <typename T>
-inline typename Internals::enable_if<Internals::is_same<T, JsonArray>::value,
-                                     JsonArray>::type
+inline typename enable_if<is_same<T, JsonArray>::value, JsonArray>::type
 JsonVariant::to() {
   if (!_data) return JsonArray();
-  _data->type = Internals::JSON_ARRAY;
+  _data->type = JSON_ARRAY;
   _data->content.asArray.head = 0;
   _data->content.asArray.tail = 0;
   return JsonArray(_memoryPool, &_data->content.asArray);
 }
 
 template <typename T>
-typename Internals::enable_if<Internals::is_same<T, JsonObject>::value,
-                              JsonObject>::type
+typename enable_if<is_same<T, JsonObject>::value, JsonObject>::type
 JsonVariant::to() {
   if (!_data) return JsonObject();
-  _data->type = Internals::JSON_OBJECT;
+  _data->type = JSON_OBJECT;
   _data->content.asObject.head = 0;
   _data->content.asObject.tail = 0;
   return JsonObject(_memoryPool, &_data->content.asObject);
 }
 
 template <typename T>
-typename Internals::enable_if<Internals::is_same<T, JsonVariant>::value,
-                              JsonVariant>::type
+typename enable_if<is_same<T, JsonVariant>::value, JsonVariant>::type
 JsonVariant::to() {
   if (!_data) return JsonVariant();
-  _data->type = Internals::JSON_NULL;
+  _data->type = JSON_NULL;
   return *this;
 }
 
 template <typename Visitor>
 inline void JsonVariant::accept(Visitor& visitor) const {
-  using namespace Internals;
   if (!_data) return visitor.visitNull();
 
   switch (_data->type) {
@@ -147,4 +138,4 @@ inline void JsonVariant::accept(Visitor& visitor) const {
       return visitor.visitNull();
   }
 }
-}  // namespace ArduinoJson
+}  // namespace ARDUINOJSON_NAMESPACE
diff --git a/src/ArduinoJson/JsonVariantOr.hpp b/src/ArduinoJson/JsonVariantOr.hpp
index 912831f7..0cdd3064 100644
--- a/src/ArduinoJson/JsonVariantOr.hpp
+++ b/src/ArduinoJson/JsonVariantOr.hpp
@@ -8,8 +8,7 @@
 #include "Polyfills/attributes.hpp"
 #include "Polyfills/type_traits.hpp"
 
-namespace ArduinoJson {
-namespace Internals {
+namespace ARDUINOJSON_NAMESPACE {
 
 template <typename TImpl>
 class JsonVariantOr {
@@ -47,5 +46,4 @@ class JsonVariantOr {
     return static_cast<const TImpl *>(this);
   }
 };
-}  // namespace Internals
-}  // namespace ArduinoJson
+}  // namespace ARDUINOJSON_NAMESPACE
diff --git a/src/ArduinoJson/JsonVariantSubscripts.hpp b/src/ArduinoJson/JsonVariantSubscripts.hpp
index 3b5a5eb1..831afac4 100644
--- a/src/ArduinoJson/JsonVariantSubscripts.hpp
+++ b/src/ArduinoJson/JsonVariantSubscripts.hpp
@@ -9,10 +9,9 @@
 #include "Polyfills/type_traits.hpp"
 #include "Strings/StringTypes.hpp"
 
-namespace ArduinoJson {
+namespace ARDUINOJSON_NAMESPACE {
 class JsonArray;
 class JsonObject;
-namespace Internals {
 
 // Forward declarations.
 class JsonArraySubscript;
@@ -73,5 +72,4 @@ class JsonVariantSubscripts {
     return static_cast<const TImpl *>(this);
   }
 };
-}  // namespace Internals
-}  // namespace ArduinoJson
+}  // namespace ARDUINOJSON_NAMESPACE
diff --git a/src/ArduinoJson/Memory/AllocableInMemoryPool.hpp b/src/ArduinoJson/Memory/AllocableInMemoryPool.hpp
index fff91e83..7462bccc 100644
--- a/src/ArduinoJson/Memory/AllocableInMemoryPool.hpp
+++ b/src/ArduinoJson/Memory/AllocableInMemoryPool.hpp
@@ -6,8 +6,7 @@
 
 #include "MemoryPool.hpp"
 
-namespace ArduinoJson {
-namespace Internals {
+namespace ARDUINOJSON_NAMESPACE {
 
 class AllocableInMemoryPool {
  public:
@@ -17,5 +16,4 @@ class AllocableInMemoryPool {
 
   void operator delete(void *, MemoryPool *)NOEXCEPT {}
 };
-}  // namespace Internals
-}  // namespace ArduinoJson
+}  // namespace ARDUINOJSON_NAMESPACE
diff --git a/src/ArduinoJson/Memory/DynamicMemoryPool.hpp b/src/ArduinoJson/Memory/DynamicMemoryPool.hpp
index ff99e9d6..7d5519e1 100644
--- a/src/ArduinoJson/Memory/DynamicMemoryPool.hpp
+++ b/src/ArduinoJson/Memory/DynamicMemoryPool.hpp
@@ -18,8 +18,7 @@
 #pragma GCC diagnostic ignored "-Wnon-virtual-dtor"
 #endif
 
-namespace ArduinoJson {
-namespace Internals {
+namespace ARDUINOJSON_NAMESPACE {
 class DefaultAllocator {
  public:
   void* allocate(size_t size) {
@@ -156,8 +155,7 @@ class DynamicMemoryPoolBase : public MemoryPool {
 // You are strongly encouraged to consider using StaticMemoryPool which is much
 // more suitable for embedded systems.
 typedef DynamicMemoryPoolBase<DefaultAllocator> DynamicMemoryPool;
-}  // namespace Internals
-}  // namespace ArduinoJson
+}  // namespace ARDUINOJSON_NAMESPACE
 
 #if defined(__clang__)
 #pragma clang diagnostic pop
diff --git a/src/ArduinoJson/Memory/MemoryPool.hpp b/src/ArduinoJson/Memory/MemoryPool.hpp
index 2cb435d1..3ed98b5c 100644
--- a/src/ArduinoJson/Memory/MemoryPool.hpp
+++ b/src/ArduinoJson/Memory/MemoryPool.hpp
@@ -11,8 +11,7 @@
 #include "../Configuration.hpp"
 #include "../Polyfills/attributes.hpp"
 
-namespace ArduinoJson {
-namespace Internals {
+namespace ARDUINOJSON_NAMESPACE {
 // Handle the memory management (done in derived classes) and calls the parser.
 // This abstract class is implemented by StaticMemoryPool which implements a
 // fixed memory allocation.
@@ -38,5 +37,4 @@ class MemoryPool {
 #endif
   }
 };
-}  // namespace Internals
-}  // namespace ArduinoJson
+}  // namespace ARDUINOJSON_NAMESPACE
diff --git a/src/ArduinoJson/Memory/StaticMemoryPool.hpp b/src/ArduinoJson/Memory/StaticMemoryPool.hpp
index a5de4e9d..5c15ab44 100644
--- a/src/ArduinoJson/Memory/StaticMemoryPool.hpp
+++ b/src/ArduinoJson/Memory/StaticMemoryPool.hpp
@@ -7,8 +7,7 @@
 #include "../Polyfills/mpl/max.hpp"
 #include "MemoryPool.hpp"
 
-namespace ArduinoJson {
-namespace Internals {
+namespace ARDUINOJSON_NAMESPACE {
 
 class StaticMemoryPoolBase : public MemoryPool {
  public:
@@ -117,8 +116,7 @@ class StaticMemoryPool : public StaticMemoryPoolBase {
  private:
   char _buffer[ACTUAL_CAPACITY];
 };
-}  // namespace Internals
-}  // namespace ArduinoJson
+}  // namespace ARDUINOJSON_NAMESPACE
 
 #if defined(__clang__)
 #pragma clang diagnostic pop
diff --git a/src/ArduinoJson/MsgPack/MsgPackDeserializer.hpp b/src/ArduinoJson/MsgPack/MsgPackDeserializer.hpp
index fb35e06c..7c2c390d 100644
--- a/src/ArduinoJson/MsgPack/MsgPackDeserializer.hpp
+++ b/src/ArduinoJson/MsgPack/MsgPackDeserializer.hpp
@@ -11,8 +11,7 @@
 #include "./endianess.hpp"
 #include "./ieee754.hpp"
 
-namespace ArduinoJson {
-namespace Internals {
+namespace ARDUINOJSON_NAMESPACE {
 
 template <typename TReader, typename TStringStorage>
 class MsgPackDeserializer {
@@ -69,7 +68,7 @@ class MsgPackDeserializer {
         return readInteger<uint32_t>(variant);
 
       case 0xcf:
-#if ARDUINOJSON_USE_LONG_LONG || ARDUINOJSON_USE_INT64
+#if ARDUINOJSON_USE_LONG_LONG
         return readInteger<uint64_t>(variant);
 #else
         readInteger<uint32_t>();
@@ -86,7 +85,7 @@ class MsgPackDeserializer {
         return readInteger<int32_t>(variant);
 
       case 0xd3:
-#if ARDUINOJSON_USE_LONG_LONG || ARDUINOJSON_USE_INT64
+#if ARDUINOJSON_USE_LONG_LONG
         return readInteger<int64_t>(variant);
 #else
         if (!skip(4)) return DeserializationError::IncompleteInput;
@@ -297,30 +296,25 @@ class MsgPackDeserializer {
   TStringStorage _stringStorage;
   uint8_t _nestingLimit;
 };
-}  // namespace Internals
 
 template <typename TDocument, typename TInput>
 DeserializationError deserializeMsgPack(TDocument &doc, const TInput &input) {
-  using namespace Internals;
   return deserialize<MsgPackDeserializer>(doc, input);
 }
 
 template <typename TDocument, typename TInput>
 DeserializationError deserializeMsgPack(TDocument &doc, TInput *input) {
-  using namespace Internals;
   return deserialize<MsgPackDeserializer>(doc, input);
 }
 
 template <typename TDocument, typename TInput>
 DeserializationError deserializeMsgPack(TDocument &doc, TInput *input,
                                         size_t inputSize) {
-  using namespace Internals;
   return deserialize<MsgPackDeserializer>(doc, input, inputSize);
 }
 
 template <typename TDocument, typename TInput>
 DeserializationError deserializeMsgPack(TDocument &doc, TInput &input) {
-  using namespace Internals;
   return deserialize<MsgPackDeserializer>(doc, input);
 }
-}  // namespace ArduinoJson
+}  // namespace ARDUINOJSON_NAMESPACE
diff --git a/src/ArduinoJson/MsgPack/MsgPackSerializer.hpp b/src/ArduinoJson/MsgPack/MsgPackSerializer.hpp
index 109674dc..875d67c4 100644
--- a/src/ArduinoJson/MsgPack/MsgPackSerializer.hpp
+++ b/src/ArduinoJson/MsgPack/MsgPackSerializer.hpp
@@ -10,8 +10,7 @@
 #include "../Serialization/serialize.hpp"
 #include "./endianess.hpp"
 
-namespace ArduinoJson {
-namespace Internals {
+namespace ARDUINOJSON_NAMESPACE {
 
 template <typename TWriter>
 class MsgPackSerializer {
@@ -107,7 +106,7 @@ class MsgPackSerializer {
       writeByte(0xD2);
       writeInteger(int32_t(negated));
     }
-#if ARDUINOJSON_USE_LONG_LONG || ARDUINOJSON_USE_INT64
+#if ARDUINOJSON_USE_LONG_LONG
     else {
       writeByte(0xD3);
       writeInteger(int64_t(negated));
@@ -128,7 +127,7 @@ class MsgPackSerializer {
       writeByte(0xCE);
       writeInteger(uint32_t(value));
     }
-#if ARDUINOJSON_USE_LONG_LONG || ARDUINOJSON_USE_INT64
+#if ARDUINOJSON_USE_LONG_LONG
     else {
       writeByte(0xCF);
       writeInteger(uint64_t(value));
@@ -166,25 +165,21 @@ class MsgPackSerializer {
   TWriter* _writer;
   size_t _bytesWritten;
 };
-}  // namespace Internals
 
 template <typename TSource, typename TDestination>
 inline size_t serializeMsgPack(const TSource& source, TDestination& output) {
-  using namespace Internals;
   return serialize<MsgPackSerializer>(source, output);
 }
 
 template <typename TSource, typename TDestination>
 inline size_t serializeMsgPack(const TSource& source, TDestination* output,
                                size_t size) {
-  using namespace Internals;
   return serialize<MsgPackSerializer>(source, output, size);
 }
 
 template <typename TSource>
 inline size_t measureMsgPack(const TSource& source) {
-  using namespace Internals;
   return measure<MsgPackSerializer>(source);
 }
 
-}  // namespace ArduinoJson
+}  // namespace ARDUINOJSON_NAMESPACE
diff --git a/src/ArduinoJson/MsgPack/endianess.hpp b/src/ArduinoJson/MsgPack/endianess.hpp
index c5fbe7e3..8ab7a747 100644
--- a/src/ArduinoJson/MsgPack/endianess.hpp
+++ b/src/ArduinoJson/MsgPack/endianess.hpp
@@ -7,8 +7,7 @@
 #include "../Polyfills/type_traits.hpp"
 #include "../Polyfills/utility.hpp"
 
-namespace ArduinoJson {
-namespace Internals {
+namespace ARDUINOJSON_NAMESPACE {
 
 inline void fixEndianess(uint8_t* p, integral_constant<size_t, 8>) {
   swap(p[0], p[7]);
@@ -36,5 +35,4 @@ inline void fixEndianess(T& value) {
 #endif
 }
 
-}  // namespace Internals
-}  // namespace ArduinoJson
+}  // namespace ARDUINOJSON_NAMESPACE
diff --git a/src/ArduinoJson/MsgPack/ieee754.hpp b/src/ArduinoJson/MsgPack/ieee754.hpp
index 19e7f285..afc9af2f 100644
--- a/src/ArduinoJson/MsgPack/ieee754.hpp
+++ b/src/ArduinoJson/MsgPack/ieee754.hpp
@@ -4,8 +4,7 @@
 
 #pragma once
 
-namespace ArduinoJson {
-namespace Internals {
+namespace ARDUINOJSON_NAMESPACE {
 
 inline void doubleToFloat(const uint8_t d[8], uint8_t f[4]) {
   f[0] = uint8_t((d[0] & 0xC0) | (d[0] << 3 & 0x3f) | (d[1] >> 5));
@@ -14,5 +13,4 @@ inline void doubleToFloat(const uint8_t d[8], uint8_t f[4]) {
   f[3] = uint8_t((d[3] << 3) | (d[4] >> 5));
 }
 
-}  // namespace Internals
-}  // namespace ArduinoJson
+}  // namespace ARDUINOJSON_NAMESPACE
diff --git a/src/ArduinoJson/Namespace.hpp b/src/ArduinoJson/Namespace.hpp
new file mode 100644
index 00000000..be412ce3
--- /dev/null
+++ b/src/ArduinoJson/Namespace.hpp
@@ -0,0 +1,22 @@
+// ArduinoJson - arduinojson.org
+// Copyright Benoit Blanchon 2014-2018
+// MIT License
+
+#pragma once
+
+#include "version.hpp"
+
+#include "Configuration.hpp"
+
+#define ARDUINOJSON_DO_CONCAT(A, B) A##B
+#define ARDUINOJSON_CONCAT2(A, B) ARDUINOJSON_DO_CONCAT(A, B)
+#define ARDUINOJSON_CONCAT4(A, B, C, D) \
+  ARDUINOJSON_CONCAT2(ARDUINOJSON_CONCAT2(A, B), ARDUINOJSON_CONCAT2(C, D))
+#define ARDUINOJSON_CONCAT8(A, B, C, D, E, F, G, H)    \
+  ARDUINOJSON_CONCAT2(ARDUINOJSON_CONCAT4(A, B, C, D), \
+                      ARDUINOJSON_CONCAT4(E, F, G, H))
+
+#define ARDUINOJSON_NAMESPACE                                                  \
+  ARDUINOJSON_CONCAT8(ArduinoJson, ARDUINOJSON_VERSION_MAJOR,                  \
+                      ARDUINOJSON_VERSION_MINOR, ARDUINOJSON_VERSION_REVISION, \
+                      _, ARDUINOJSON_USE_LONG_LONG, _, ARDUINOJSON_USE_DOUBLE)
diff --git a/src/ArduinoJson/Numbers/FloatParts.hpp b/src/ArduinoJson/Numbers/FloatParts.hpp
index d7c34274..1744549d 100644
--- a/src/ArduinoJson/Numbers/FloatParts.hpp
+++ b/src/ArduinoJson/Numbers/FloatParts.hpp
@@ -8,8 +8,7 @@
 #include "../Polyfills/math.hpp"
 #include "./FloatTraits.hpp"
 
-namespace ArduinoJson {
-namespace Internals {
+namespace ARDUINOJSON_NAMESPACE {
 
 template <typename TFloat>
 struct FloatParts {
@@ -85,5 +84,4 @@ struct FloatParts {
     return powersOf10;
   }
 };
-}  // namespace Internals
-}  // namespace ArduinoJson
+}  // namespace ARDUINOJSON_NAMESPACE
diff --git a/src/ArduinoJson/Numbers/FloatTraits.hpp b/src/ArduinoJson/Numbers/FloatTraits.hpp
index 3e3dd578..e1e7a108 100644
--- a/src/ArduinoJson/Numbers/FloatTraits.hpp
+++ b/src/ArduinoJson/Numbers/FloatTraits.hpp
@@ -9,8 +9,7 @@
 #include "../Configuration.hpp"
 #include "../Polyfills/math.hpp"
 
-namespace ArduinoJson {
-namespace Internals {
+namespace ARDUINOJSON_NAMESPACE {
 
 template <typename T, size_t = sizeof(T)>
 struct FloatTraits {};
@@ -167,5 +166,4 @@ struct FloatTraits<T, 4 /*32bits*/> {
     return forge(0x7f800000);
   }
 };
-}  // namespace Internals
-}  // namespace ArduinoJson
+}  // namespace ARDUINOJSON_NAMESPACE
diff --git a/src/ArduinoJson/Numbers/isFloat.hpp b/src/ArduinoJson/Numbers/isFloat.hpp
index 5e241ede..c4832040 100644
--- a/src/ArduinoJson/Numbers/isFloat.hpp
+++ b/src/ArduinoJson/Numbers/isFloat.hpp
@@ -7,8 +7,7 @@
 #include <string.h>  // for strcmp
 #include "../Polyfills/ctype.hpp"
 
-namespace ArduinoJson {
-namespace Internals {
+namespace ARDUINOJSON_NAMESPACE {
 
 inline bool isFloat(const char* s) {
   if (!s) return false;
@@ -34,5 +33,4 @@ inline bool isFloat(const char* s) {
 
   return *s == '\0';
 }
-}  // namespace Internals
-}  // namespace ArduinoJson
+}  // namespace ARDUINOJSON_NAMESPACE
diff --git a/src/ArduinoJson/Numbers/isInteger.hpp b/src/ArduinoJson/Numbers/isInteger.hpp
index e1457f13..88df71de 100644
--- a/src/ArduinoJson/Numbers/isInteger.hpp
+++ b/src/ArduinoJson/Numbers/isInteger.hpp
@@ -6,8 +6,7 @@
 
 #include "../Polyfills/ctype.hpp"
 
-namespace ArduinoJson {
-namespace Internals {
+namespace ARDUINOJSON_NAMESPACE {
 
 inline bool isInteger(const char* s) {
   if (!s || !*s) return false;
@@ -15,5 +14,4 @@ inline bool isInteger(const char* s) {
   while (isdigit(*s)) s++;
   return *s == '\0';
 }
-}  // namespace Internals
-}  // namespace ArduinoJson
+}  // namespace ARDUINOJSON_NAMESPACE
diff --git a/src/ArduinoJson/Numbers/parseFloat.hpp b/src/ArduinoJson/Numbers/parseFloat.hpp
index e50f9059..b0dd4395 100644
--- a/src/ArduinoJson/Numbers/parseFloat.hpp
+++ b/src/ArduinoJson/Numbers/parseFloat.hpp
@@ -8,8 +8,7 @@
 #include "../Polyfills/ctype.hpp"
 #include "../Polyfills/math.hpp"
 
-namespace ArduinoJson {
-namespace Internals {
+namespace ARDUINOJSON_NAMESPACE {
 
 template <typename T>
 inline T parseFloat(const char* s) {
@@ -86,5 +85,4 @@ inline T parseFloat(const char* s) {
 
   return negative_result ? -result : result;
 }
-}  // namespace Internals
-}  // namespace ArduinoJson
+}  // namespace ARDUINOJSON_NAMESPACE
diff --git a/src/ArduinoJson/Numbers/parseInteger.hpp b/src/ArduinoJson/Numbers/parseInteger.hpp
index 11f2257b..e0a29ea6 100644
--- a/src/ArduinoJson/Numbers/parseInteger.hpp
+++ b/src/ArduinoJson/Numbers/parseInteger.hpp
@@ -9,8 +9,7 @@
 #include "../Configuration.hpp"
 #include "../Polyfills/ctype.hpp"
 
-namespace ArduinoJson {
-namespace Internals {
+namespace ARDUINOJSON_NAMESPACE {
 template <typename T>
 T parseInteger(const char *s) {
   if (!s) return 0;  // NULL
@@ -37,5 +36,4 @@ T parseInteger(const char *s) {
 
   return negative_result ? T(~result + 1) : result;
 }
-}  // namespace Internals
-}  // namespace ArduinoJson
+}  // namespace ARDUINOJSON_NAMESPACE
diff --git a/src/ArduinoJson/Polyfills/ctype.hpp b/src/ArduinoJson/Polyfills/ctype.hpp
index 2d52703c..f89bb177 100644
--- a/src/ArduinoJson/Polyfills/ctype.hpp
+++ b/src/ArduinoJson/Polyfills/ctype.hpp
@@ -4,8 +4,7 @@
 
 #pragma once
 
-namespace ArduinoJson {
-namespace Internals {
+namespace ARDUINOJSON_NAMESPACE {
 
 inline bool isdigit(char c) {
   return '0' <= c && c <= '9';
@@ -14,5 +13,4 @@ inline bool isdigit(char c) {
 inline bool issign(char c) {
   return '-' == c || c == '+';
 }
-}
-}
+}  // namespace ARDUINOJSON_NAMESPACE
diff --git a/src/ArduinoJson/Polyfills/math.hpp b/src/ArduinoJson/Polyfills/math.hpp
index 171021dd..f9974407 100644
--- a/src/ArduinoJson/Polyfills/math.hpp
+++ b/src/ArduinoJson/Polyfills/math.hpp
@@ -4,8 +4,7 @@
 
 #pragma once
 
-namespace ArduinoJson {
-namespace Internals {
+namespace ARDUINOJSON_NAMESPACE {
 
 // Some libraries #define isnan() and isinf() so we need to check before
 // using this name
@@ -23,5 +22,4 @@ bool isinf(T x) {
   return x != 0.0 && x * 2 == x;
 }
 #endif
-}  // namespace Internals
-}  // namespace ArduinoJson
+}  // namespace ARDUINOJSON_NAMESPACE
diff --git a/src/ArduinoJson/Polyfills/mpl/max.hpp b/src/ArduinoJson/Polyfills/mpl/max.hpp
index 13d65371..d8792b86 100644
--- a/src/ArduinoJson/Polyfills/mpl/max.hpp
+++ b/src/ArduinoJson/Polyfills/mpl/max.hpp
@@ -6,8 +6,7 @@
 
 #include <stdlib.h>  // for size_t
 
-namespace ArduinoJson {
-namespace Internals {
+namespace ARDUINOJSON_NAMESPACE {
 
 // A meta-function that returns the highest value
 template <size_t X, size_t Y, bool MaxIsX = (X > Y)>
@@ -22,5 +21,4 @@ template <size_t X, size_t Y>
 struct Max<X, Y, false> {
   static const size_t value = Y;
 };
-}  // namespace Internals
-}  // namespace ArduinoJson
+}  // namespace ARDUINOJSON_NAMESPACE
diff --git a/src/ArduinoJson/Polyfills/type_traits/enable_if.hpp b/src/ArduinoJson/Polyfills/type_traits/enable_if.hpp
index 70dd92e6..a57bc000 100644
--- a/src/ArduinoJson/Polyfills/type_traits/enable_if.hpp
+++ b/src/ArduinoJson/Polyfills/type_traits/enable_if.hpp
@@ -4,8 +4,7 @@
 
 #pragma once
 
-namespace ArduinoJson {
-namespace Internals {
+namespace ARDUINOJSON_NAMESPACE {
 
 // A meta-function that return the type T if Condition is true.
 template <bool Condition, typename T = void>
@@ -15,5 +14,4 @@ template <typename T>
 struct enable_if<true, T> {
   typedef T type;
 };
-}  // namespace Internals
-}  // namespace ArduinoJson
+}  // namespace ARDUINOJSON_NAMESPACE
diff --git a/src/ArduinoJson/Polyfills/type_traits/integral_constant.hpp b/src/ArduinoJson/Polyfills/type_traits/integral_constant.hpp
index 7ce931c3..cd275c58 100644
--- a/src/ArduinoJson/Polyfills/type_traits/integral_constant.hpp
+++ b/src/ArduinoJson/Polyfills/type_traits/integral_constant.hpp
@@ -4,8 +4,7 @@
 
 #pragma once
 
-namespace ArduinoJson {
-namespace Internals {
+namespace ARDUINOJSON_NAMESPACE {
 
 template <typename T, T v>
 struct integral_constant {
@@ -15,5 +14,4 @@ struct integral_constant {
 typedef integral_constant<bool, true> true_type;
 typedef integral_constant<bool, false> false_type;
 
-}  // namespace Internals
-}  // namespace ArduinoJson
+}  // namespace ARDUINOJSON_NAMESPACE
diff --git a/src/ArduinoJson/Polyfills/type_traits/is_array.hpp b/src/ArduinoJson/Polyfills/type_traits/is_array.hpp
index 17075d4a..34321e56 100644
--- a/src/ArduinoJson/Polyfills/type_traits/is_array.hpp
+++ b/src/ArduinoJson/Polyfills/type_traits/is_array.hpp
@@ -4,8 +4,7 @@
 
 #pragma once
 
-namespace ArduinoJson {
-namespace Internals {
+namespace ARDUINOJSON_NAMESPACE {
 
 template <typename T>
 struct is_array : false_type {};
@@ -15,5 +14,4 @@ struct is_array<T[]> : true_type {};
 
 template <typename T, size_t N>
 struct is_array<T[N]> : true_type {};
-}  // namespace Internals
-}  // namespace ArduinoJson
+}  // namespace ARDUINOJSON_NAMESPACE
diff --git a/src/ArduinoJson/Polyfills/type_traits/is_base_of.hpp b/src/ArduinoJson/Polyfills/type_traits/is_base_of.hpp
index be6ddeac..dc3750ee 100644
--- a/src/ArduinoJson/Polyfills/type_traits/is_base_of.hpp
+++ b/src/ArduinoJson/Polyfills/type_traits/is_base_of.hpp
@@ -4,8 +4,7 @@
 
 #pragma once
 
-namespace ArduinoJson {
-namespace Internals {
+namespace ARDUINOJSON_NAMESPACE {
 
 // A meta-function that returns true if Derived inherits from TBase is an
 // integral type.
@@ -23,5 +22,4 @@ class is_base_of {
     value = sizeof(probe(reinterpret_cast<TDerived *>(0))) == sizeof(Yes)
   };
 };
-}  // namespace Internals
-}  // namespace ArduinoJson
+}  // namespace ARDUINOJSON_NAMESPACE
diff --git a/src/ArduinoJson/Polyfills/type_traits/is_const.hpp b/src/ArduinoJson/Polyfills/type_traits/is_const.hpp
index 0a2dfda9..9e12c33d 100644
--- a/src/ArduinoJson/Polyfills/type_traits/is_const.hpp
+++ b/src/ArduinoJson/Polyfills/type_traits/is_const.hpp
@@ -6,8 +6,7 @@
 
 #include "integral_constant.hpp"
 
-namespace ArduinoJson {
-namespace Internals {
+namespace ARDUINOJSON_NAMESPACE {
 
 // A meta-function that return the type T without the const modifier
 template <typename T>
@@ -15,5 +14,4 @@ struct is_const : false_type {};
 
 template <typename T>
 struct is_const<const T> : true_type {};
-}  // namespace Internals
-}  // namespace ArduinoJson
+}  // namespace ARDUINOJSON_NAMESPACE
diff --git a/src/ArduinoJson/Polyfills/type_traits/is_floating_point.hpp b/src/ArduinoJson/Polyfills/type_traits/is_floating_point.hpp
index 24e74ab7..dc3a32cf 100644
--- a/src/ArduinoJson/Polyfills/type_traits/is_floating_point.hpp
+++ b/src/ArduinoJson/Polyfills/type_traits/is_floating_point.hpp
@@ -6,8 +6,7 @@
 
 #include "integral_constant.hpp"
 
-namespace ArduinoJson {
-namespace Internals {
+namespace ARDUINOJSON_NAMESPACE {
 
 template <typename>
 struct is_floating_point : false_type {};
@@ -17,5 +16,4 @@ struct is_floating_point<float> : true_type {};
 
 template <>
 struct is_floating_point<double> : true_type {};
-}  // namespace Internals
-}  // namespace ArduinoJson
+}  // namespace ARDUINOJSON_NAMESPACE
diff --git a/src/ArduinoJson/Polyfills/type_traits/is_integral.hpp b/src/ArduinoJson/Polyfills/type_traits/is_integral.hpp
index abd86050..1c320382 100644
--- a/src/ArduinoJson/Polyfills/type_traits/is_integral.hpp
+++ b/src/ArduinoJson/Polyfills/type_traits/is_integral.hpp
@@ -7,8 +7,7 @@
 #include "../../Configuration.hpp"
 #include "is_same.hpp"
 
-namespace ArduinoJson {
-namespace Internals {
+namespace ARDUINOJSON_NAMESPACE {
 
 // A meta-function that returns true if T is an integral type.
 template <typename T>
@@ -18,19 +17,19 @@ struct is_integral {
       is_same<T, signed short>::value || is_same<T, unsigned short>::value ||
       is_same<T, signed int>::value || is_same<T, unsigned int>::value ||
       is_same<T, signed long>::value || is_same<T, unsigned long>::value ||
-#if ARDUINOJSON_USE_LONG_LONG
-      is_same<T, unsigned long long>::value ||
+#if ARDUINOJSON_HAS_LONG_LONG
       is_same<T, signed long long>::value ||
+      is_same<T, unsigned long long>::value ||
 #endif
-#if ARDUINOJSON_USE_INT64
-      is_same<T, unsigned __int64>::value ||
+#if ARDUINOJSON_HAS_INT64
       is_same<T, signed __int64>::value ||
+      is_same<T, unsigned __int64>::value ||
 #endif
       is_same<T, char>::value;
+
   // CAUTION: differs from std::is_integral as it doesn't include bool
 };
 
 template <typename T>
 struct is_integral<const T> : is_integral<T> {};
-}  // namespace Internals
-}  // namespace ArduinoJson
+}  // namespace ARDUINOJSON_NAMESPACE
diff --git a/src/ArduinoJson/Polyfills/type_traits/is_same.hpp b/src/ArduinoJson/Polyfills/type_traits/is_same.hpp
index 920f5b54..0bf60f63 100644
--- a/src/ArduinoJson/Polyfills/type_traits/is_same.hpp
+++ b/src/ArduinoJson/Polyfills/type_traits/is_same.hpp
@@ -6,8 +6,7 @@
 
 #include "integral_constant.hpp"
 
-namespace ArduinoJson {
-namespace Internals {
+namespace ARDUINOJSON_NAMESPACE {
 
 // A meta-function that returns true if types T and U are the same.
 template <typename T, typename U>
@@ -15,5 +14,4 @@ struct is_same : false_type {};
 
 template <typename T>
 struct is_same<T, T> : true_type {};
-}  // namespace Internals
-}  // namespace ArduinoJson
+}  // namespace ARDUINOJSON_NAMESPACE
diff --git a/src/ArduinoJson/Polyfills/type_traits/is_signed.hpp b/src/ArduinoJson/Polyfills/type_traits/is_signed.hpp
index b145c5ea..ff596987 100644
--- a/src/ArduinoJson/Polyfills/type_traits/is_signed.hpp
+++ b/src/ArduinoJson/Polyfills/type_traits/is_signed.hpp
@@ -5,8 +5,7 @@
 #pragma once
 
 #include "integral_constant.hpp"
-namespace ArduinoJson {
-namespace Internals {
+namespace ARDUINOJSON_NAMESPACE {
 
 template <typename>
 struct is_signed : false_type {};
@@ -32,13 +31,13 @@ struct is_signed<float> : true_type {};
 template <>
 struct is_signed<double> : true_type {};
 
-#if ARDUINOJSON_USE_LONG_LONG
+#if ARDUINOJSON_HAS_LONG_LONG
 template <>
 struct is_signed<signed long long> : true_type {};
 #endif
-#if ARDUINOJSON_USE_INT64
+
+#if ARDUINOJSON_HAS_INT64
 template <>
 struct is_signed<signed __int64> : true_type {};
 #endif
-}  // namespace Internals
-}  // namespace ArduinoJson
+}  // namespace ARDUINOJSON_NAMESPACE
diff --git a/src/ArduinoJson/Polyfills/type_traits/is_unsigned.hpp b/src/ArduinoJson/Polyfills/type_traits/is_unsigned.hpp
index 4de418d0..e3024e35 100644
--- a/src/ArduinoJson/Polyfills/type_traits/is_unsigned.hpp
+++ b/src/ArduinoJson/Polyfills/type_traits/is_unsigned.hpp
@@ -5,8 +5,7 @@
 #pragma once
 
 #include "integral_constant.hpp"
-namespace ArduinoJson {
-namespace Internals {
+namespace ARDUINOJSON_NAMESPACE {
 
 template <typename>
 struct is_unsigned : false_type {};
@@ -26,13 +25,13 @@ struct is_unsigned<unsigned int> : true_type {};
 template <>
 struct is_unsigned<unsigned long> : true_type {};
 
-#if ARDUINOJSON_USE_LONG_LONG
-template <>
-struct is_unsigned<unsigned long long> : true_type {};
-#endif
-#if ARDUINOJSON_USE_INT64
+#if ARDUINOJSON_HAS_INT64
 template <>
 struct is_unsigned<unsigned __int64> : true_type {};
 #endif
-}  // namespace Internals
-}  // namespace ArduinoJson
+
+#if ARDUINOJSON_HAS_LONG_LONG
+template <>
+struct is_unsigned<unsigned long long> : true_type {};
+#endif
+}  // namespace ARDUINOJSON_NAMESPACE
diff --git a/src/ArduinoJson/Polyfills/type_traits/remove_const.hpp b/src/ArduinoJson/Polyfills/type_traits/remove_const.hpp
index 9cb7421b..6b8b6260 100644
--- a/src/ArduinoJson/Polyfills/type_traits/remove_const.hpp
+++ b/src/ArduinoJson/Polyfills/type_traits/remove_const.hpp
@@ -4,8 +4,7 @@
 
 #pragma once
 
-namespace ArduinoJson {
-namespace Internals {
+namespace ARDUINOJSON_NAMESPACE {
 
 // A meta-function that return the type T without the const modifier
 template <typename T>
@@ -16,5 +15,4 @@ template <typename T>
 struct remove_const<const T> {
   typedef T type;
 };
-}  // namespace Internals
-}  // namespace ArduinoJson
+}  // namespace ARDUINOJSON_NAMESPACE
diff --git a/src/ArduinoJson/Polyfills/type_traits/remove_reference.hpp b/src/ArduinoJson/Polyfills/type_traits/remove_reference.hpp
index f0103dd2..ad44d291 100644
--- a/src/ArduinoJson/Polyfills/type_traits/remove_reference.hpp
+++ b/src/ArduinoJson/Polyfills/type_traits/remove_reference.hpp
@@ -4,8 +4,7 @@
 
 #pragma once
 
-namespace ArduinoJson {
-namespace Internals {
+namespace ARDUINOJSON_NAMESPACE {
 
 // A meta-function that return the type T without the reference modifier.
 template <typename T>
@@ -16,5 +15,4 @@ template <typename T>
 struct remove_reference<T&> {
   typedef T type;
 };
-}  // namespace Internals
-}  // namespace ArduinoJson
+}  // namespace ARDUINOJSON_NAMESPACE
diff --git a/src/ArduinoJson/Polyfills/utility.hpp b/src/ArduinoJson/Polyfills/utility.hpp
index 5efd885c..a28d31c9 100644
--- a/src/ArduinoJson/Polyfills/utility.hpp
+++ b/src/ArduinoJson/Polyfills/utility.hpp
@@ -4,13 +4,11 @@
 
 #pragma once
 
-namespace ArduinoJson {
-namespace Internals {
+namespace ARDUINOJSON_NAMESPACE {
 template <typename T>
 inline void swap(T& a, T& b) {
   T t(a);
   a = b;
   b = t;
 }
-}  // namespace Internals
-}  // namespace ArduinoJson
+}  // namespace ARDUINOJSON_NAMESPACE
diff --git a/src/ArduinoJson/Serialization/DummyWriter.hpp b/src/ArduinoJson/Serialization/DummyWriter.hpp
index c2c26a04..aca2ba53 100644
--- a/src/ArduinoJson/Serialization/DummyWriter.hpp
+++ b/src/ArduinoJson/Serialization/DummyWriter.hpp
@@ -4,8 +4,7 @@
 
 #pragma once
 
-namespace ArduinoJson {
-namespace Internals {
+namespace ARDUINOJSON_NAMESPACE {
 
 class DummyWriter {
  public:
@@ -17,5 +16,4 @@ class DummyWriter {
     return n;
   }
 };
-}  // namespace Internals
-}  // namespace ArduinoJson
+}  // namespace ARDUINOJSON_NAMESPACE
diff --git a/src/ArduinoJson/Serialization/DynamicStringWriter.hpp b/src/ArduinoJson/Serialization/DynamicStringWriter.hpp
index 75879ced..7ae80492 100644
--- a/src/ArduinoJson/Serialization/DynamicStringWriter.hpp
+++ b/src/ArduinoJson/Serialization/DynamicStringWriter.hpp
@@ -14,8 +14,7 @@
 #include <string>
 #endif
 
-namespace ArduinoJson {
-namespace Internals {
+namespace ARDUINOJSON_NAMESPACE {
 
 template <typename>
 struct IsWriteableString : false_type {};
@@ -77,5 +76,4 @@ class DynamicStringWriter<std::string> {
   std::string *_str;
 };
 #endif
-}  // namespace Internals
-}  // namespace ArduinoJson
+}  // namespace ARDUINOJSON_NAMESPACE
diff --git a/src/ArduinoJson/Serialization/StaticStringWriter.hpp b/src/ArduinoJson/Serialization/StaticStringWriter.hpp
index 0384b621..aa9ad4c8 100644
--- a/src/ArduinoJson/Serialization/StaticStringWriter.hpp
+++ b/src/ArduinoJson/Serialization/StaticStringWriter.hpp
@@ -4,8 +4,7 @@
 
 #pragma once
 
-namespace ArduinoJson {
-namespace Internals {
+namespace ARDUINOJSON_NAMESPACE {
 
 // A Print implementation that allows to write in a char[]
 class StaticStringWriter {
@@ -35,5 +34,4 @@ class StaticStringWriter {
   char *end;
   char *p;
 };
-}  // namespace Internals
-}  // namespace ArduinoJson
+}  // namespace ARDUINOJSON_NAMESPACE
diff --git a/src/ArduinoJson/Serialization/StreamWriter.hpp b/src/ArduinoJson/Serialization/StreamWriter.hpp
index 94cc39d1..06515d13 100644
--- a/src/ArduinoJson/Serialization/StreamWriter.hpp
+++ b/src/ArduinoJson/Serialization/StreamWriter.hpp
@@ -10,8 +10,7 @@
 
 #include <ostream>
 
-namespace ArduinoJson {
-namespace Internals {
+namespace ARDUINOJSON_NAMESPACE {
 
 class StreamWriter {
  public:
@@ -34,7 +33,6 @@ class StreamWriter {
 
   std::ostream& _os;
 };
-}  // namespace Internals
-}  // namespace ArduinoJson
+}  // namespace ARDUINOJSON_NAMESPACE
 
 #endif  // ARDUINOJSON_ENABLE_STD_STREAM
diff --git a/src/ArduinoJson/Serialization/measure.hpp b/src/ArduinoJson/Serialization/measure.hpp
index 77c24d2d..67bb5788 100644
--- a/src/ArduinoJson/Serialization/measure.hpp
+++ b/src/ArduinoJson/Serialization/measure.hpp
@@ -6,8 +6,7 @@
 
 #include "./DummyWriter.hpp"
 
-namespace ArduinoJson {
-namespace Internals {
+namespace ARDUINOJSON_NAMESPACE {
 
 template <template <typename> class TSerializer, typename TSource>
 size_t measure(const TSource &source) {
@@ -17,5 +16,4 @@ size_t measure(const TSource &source) {
   return serializer.bytesWritten();
 }
 
-}  // namespace Internals
-}  // namespace ArduinoJson
+}  // namespace ARDUINOJSON_NAMESPACE
diff --git a/src/ArduinoJson/Serialization/serialize.hpp b/src/ArduinoJson/Serialization/serialize.hpp
index 4291d721..4b21468d 100644
--- a/src/ArduinoJson/Serialization/serialize.hpp
+++ b/src/ArduinoJson/Serialization/serialize.hpp
@@ -11,8 +11,7 @@
 #include "./StreamWriter.hpp"
 #endif
 
-namespace ArduinoJson {
-namespace Internals {
+namespace ARDUINOJSON_NAMESPACE {
 
 template <template <typename> class TSerializer, typename TSource,
           typename TPrint>
@@ -51,5 +50,4 @@ typename enable_if<IsWriteableString<TString>::value, size_t>::type serialize(
   return serialize<TSerializer>(source, writer);
 }
 
-}  // namespace Internals
-}  // namespace ArduinoJson
+}  // namespace ARDUINOJSON_NAMESPACE
diff --git a/src/ArduinoJson/SerializedValue.hpp b/src/ArduinoJson/SerializedValue.hpp
index bf7cfa6f..2553d680 100644
--- a/src/ArduinoJson/SerializedValue.hpp
+++ b/src/ArduinoJson/SerializedValue.hpp
@@ -6,9 +6,8 @@
 
 #include "Strings/StringTypes.hpp"
 
-namespace ArduinoJson {
+namespace ARDUINOJSON_NAMESPACE {
 
-namespace Internals {
 // A special type of data that can be used to insert pregenerated JSON portions.
 template <typename T>
 class SerializedValue {
@@ -51,20 +50,19 @@ class SerializedValue<TChar*> {
   TChar* _data;
   size_t _size;
 };
-}  // namespace Internals
 
 template <typename T>
-inline Internals::SerializedValue<T> serialized(T str) {
-  return Internals::SerializedValue<T>(str);
+inline SerializedValue<T> serialized(T str) {
+  return SerializedValue<T>(str);
 }
 
 template <typename TChar>
-inline Internals::SerializedValue<TChar*> serialized(TChar* p) {
-  return Internals::SerializedValue<TChar*>(p, Internals::makeString(p).size());
+inline SerializedValue<TChar*> serialized(TChar* p) {
+  return SerializedValue<TChar*>(p, makeString(p).size());
 }
 
 template <typename TChar>
-inline Internals::SerializedValue<TChar*> serialized(TChar* p, size_t n) {
-  return Internals::SerializedValue<TChar*>(p, n);
+inline SerializedValue<TChar*> serialized(TChar* p, size_t n) {
+  return SerializedValue<TChar*>(p, n);
 }
-}  // namespace ArduinoJson
+}  // namespace ARDUINOJSON_NAMESPACE
diff --git a/src/ArduinoJson/StaticJsonDocument.hpp b/src/ArduinoJson/StaticJsonDocument.hpp
index 352d3497..bc6dc0d1 100644
--- a/src/ArduinoJson/StaticJsonDocument.hpp
+++ b/src/ArduinoJson/StaticJsonDocument.hpp
@@ -8,7 +8,7 @@
 #include "JsonVariant.hpp"
 #include "Memory/StaticMemoryPool.hpp"
 
-namespace ArduinoJson {
+namespace ARDUINOJSON_NAMESPACE {
 
 template <size_t CAPACITY>
 class StaticJsonDocument {
@@ -17,7 +17,7 @@ class StaticJsonDocument {
 
   StaticJsonDocument() : nestingLimit(ARDUINOJSON_DEFAULT_NESTING_LIMIT) {}
 
-  Internals::StaticMemoryPoolBase& memoryPool() {
+  StaticMemoryPoolBase& memoryPool() {
     return _memoryPool;
   }
 
@@ -27,19 +27,19 @@ class StaticJsonDocument {
   }
 
   template <typename T>
-  typename Internals::JsonVariantAs<T>::type as() const {
+  typename JsonVariantAs<T>::type as() const {
     return getVariant().template as<T>();
   }
 
   template <typename T>
-  typename Internals::JsonVariantTo<T>::type to() {
+  typename JsonVariantTo<T>::type to() {
     _memoryPool.clear();
     return getVariant().template to<T>();
   }
 
   void clear() {
     _memoryPool.clear();
-    _rootData.type = Internals::JSON_NULL;
+    _rootData.type = JSON_NULL;
   }
 
   size_t memoryUsage() const {
@@ -56,8 +56,8 @@ class StaticJsonDocument {
     return JsonVariant(&_memoryPool, &_rootData);
   }
 
-  mutable Internals::StaticMemoryPool<CAPACITY> _memoryPool;
-  mutable Internals::JsonVariantData _rootData;
+  mutable StaticMemoryPool<CAPACITY> _memoryPool;
+  mutable JsonVariantData _rootData;
 };
 
-}  // namespace ArduinoJson
+}  // namespace ARDUINOJSON_NAMESPACE
diff --git a/src/ArduinoJson/StringStorage/StringCopier.hpp b/src/ArduinoJson/StringStorage/StringCopier.hpp
index 7b44e944..20220e8e 100644
--- a/src/ArduinoJson/StringStorage/StringCopier.hpp
+++ b/src/ArduinoJson/StringStorage/StringCopier.hpp
@@ -4,8 +4,7 @@
 
 #pragma once
 
-namespace ArduinoJson {
-namespace Internals {
+namespace ARDUINOJSON_NAMESPACE {
 
 template <typename TMemoryPool>
 class StringCopier {
@@ -21,5 +20,4 @@ class StringCopier {
  private:
   TMemoryPool* _memoryPool;
 };
-}  // namespace Internals
-}  // namespace ArduinoJson
+}  // namespace ARDUINOJSON_NAMESPACE
diff --git a/src/ArduinoJson/StringStorage/StringMover.hpp b/src/ArduinoJson/StringStorage/StringMover.hpp
index 75b28815..06986e40 100644
--- a/src/ArduinoJson/StringStorage/StringMover.hpp
+++ b/src/ArduinoJson/StringStorage/StringMover.hpp
@@ -4,8 +4,7 @@
 
 #pragma once
 
-namespace ArduinoJson {
-namespace Internals {
+namespace ARDUINOJSON_NAMESPACE {
 
 template <typename TChar>
 class StringMover {
@@ -37,5 +36,4 @@ class StringMover {
  private:
   TChar* _ptr;
 };
-}  // namespace Internals
-}  // namespace ArduinoJson
+}  // namespace ARDUINOJSON_NAMESPACE
diff --git a/src/ArduinoJson/StringStorage/StringStorage.hpp b/src/ArduinoJson/StringStorage/StringStorage.hpp
index 51bb9c7b..d7c3fff3 100644
--- a/src/ArduinoJson/StringStorage/StringStorage.hpp
+++ b/src/ArduinoJson/StringStorage/StringStorage.hpp
@@ -7,8 +7,7 @@
 #include "./StringCopier.hpp"
 #include "./StringMover.hpp"
 
-namespace ArduinoJson {
-namespace Internals {
+namespace ARDUINOJSON_NAMESPACE {
 
 template <typename TMemoryPool, typename TInput, typename Enable = void>
 struct StringStorage {
@@ -40,5 +39,4 @@ typename StringStorage<TMemoryPool, TChar*>::type makeStringStorage(
     TMemoryPool& jb, TChar* input) {
   return StringStorage<TMemoryPool, TChar*>::create(jb, input);
 }
-}  // namespace Internals
-}  // namespace ArduinoJson
+}  // namespace ARDUINOJSON_NAMESPACE
diff --git a/src/ArduinoJson/Strings/ArduinoString.hpp b/src/ArduinoJson/Strings/ArduinoString.hpp
index 687d2a9a..9402de58 100644
--- a/src/ArduinoJson/Strings/ArduinoString.hpp
+++ b/src/ArduinoJson/Strings/ArduinoString.hpp
@@ -6,8 +6,7 @@
 
 #include <WString.h>
 
-namespace ArduinoJson {
-namespace Internals {
+namespace ARDUINOJSON_NAMESPACE {
 
 class ArduinoString {
  public:
@@ -56,5 +55,4 @@ inline ArduinoString makeString(const ::String& str) {
   return ArduinoString(str);
 }
 
-}  // namespace Internals
-}  // namespace ArduinoJson
+}  // namespace ARDUINOJSON_NAMESPACE
diff --git a/src/ArduinoJson/Strings/FixedSizeFlashString.hpp b/src/ArduinoJson/Strings/FixedSizeFlashString.hpp
index ef1e22a7..3fb5c8e2 100644
--- a/src/ArduinoJson/Strings/FixedSizeFlashString.hpp
+++ b/src/ArduinoJson/Strings/FixedSizeFlashString.hpp
@@ -4,8 +4,7 @@
 
 #pragma once
 
-namespace ArduinoJson {
-namespace Internals {
+namespace ARDUINOJSON_NAMESPACE {
 
 class FixedSizeFlashString {
  public:
@@ -43,5 +42,4 @@ inline FixedSizeFlashString makeString(const __FlashStringHelper* str,
                                        size_t sz) {
   return FixedSizeFlashString(str, sz);
 }
-}  // namespace Internals
-}  // namespace ArduinoJson
+}  // namespace ARDUINOJSON_NAMESPACE
diff --git a/src/ArduinoJson/Strings/FixedSizeRamString.hpp b/src/ArduinoJson/Strings/FixedSizeRamString.hpp
index b1edf391..8b599369 100644
--- a/src/ArduinoJson/Strings/FixedSizeRamString.hpp
+++ b/src/ArduinoJson/Strings/FixedSizeRamString.hpp
@@ -6,8 +6,7 @@
 
 #include <string.h>  // strcmp
 
-namespace ArduinoJson {
-namespace Internals {
+namespace ARDUINOJSON_NAMESPACE {
 
 class FixedSizeRamString {
  public:
@@ -46,5 +45,4 @@ inline FixedSizeRamString makeString(const TChar* str, size_t size) {
   return FixedSizeRamString(reinterpret_cast<const char*>(str), size);
 }
 
-}  // namespace Internals
-}  // namespace ArduinoJson
+}  // namespace ARDUINOJSON_NAMESPACE
diff --git a/src/ArduinoJson/Strings/StlString.hpp b/src/ArduinoJson/Strings/StlString.hpp
index d463c00d..a2bbfda9 100644
--- a/src/ArduinoJson/Strings/StlString.hpp
+++ b/src/ArduinoJson/Strings/StlString.hpp
@@ -6,8 +6,7 @@
 
 #include <string>
 
-namespace ArduinoJson {
-namespace Internals {
+namespace ARDUINOJSON_NAMESPACE {
 
 class StlString {
  public:
@@ -49,5 +48,4 @@ inline StlString makeString(const std::string& str) {
   return StlString(str);
 }
 
-}  // namespace Internals
-}  // namespace ArduinoJson
+}  // namespace ARDUINOJSON_NAMESPACE
diff --git a/src/ArduinoJson/Strings/StringTypes.hpp b/src/ArduinoJson/Strings/StringTypes.hpp
index 53698225..a4675e5c 100644
--- a/src/ArduinoJson/Strings/StringTypes.hpp
+++ b/src/ArduinoJson/Strings/StringTypes.hpp
@@ -6,8 +6,7 @@
 
 #include "../Polyfills/type_traits.hpp"
 
-namespace ArduinoJson {
-namespace Internals {
+namespace ARDUINOJSON_NAMESPACE {
 template <typename>
 struct IsString : false_type {};
 
@@ -16,8 +15,7 @@ struct IsString<const T> : IsString<T> {};
 
 template <typename T>
 struct IsString<T&> : IsString<T> {};
-}  // namespace Internals
-}  // namespace ArduinoJson
+}  // namespace ARDUINOJSON_NAMESPACE
 
 #include "FixedSizeRamString.hpp"
 #include "ZeroTerminatedRamString.hpp"
diff --git a/src/ArduinoJson/Strings/ZeroTerminatedFlashString.hpp b/src/ArduinoJson/Strings/ZeroTerminatedFlashString.hpp
index 4773bce0..f5f7cf3f 100644
--- a/src/ArduinoJson/Strings/ZeroTerminatedFlashString.hpp
+++ b/src/ArduinoJson/Strings/ZeroTerminatedFlashString.hpp
@@ -4,8 +4,7 @@
 
 #pragma once
 
-namespace ArduinoJson {
-namespace Internals {
+namespace ARDUINOJSON_NAMESPACE {
 
 class ZeroTerminatedFlashString {
  public:
@@ -44,5 +43,4 @@ inline ZeroTerminatedFlashString makeString(const __FlashStringHelper* str) {
 
 template <>
 struct IsString<const __FlashStringHelper*> : true_type {};
-}  // namespace Internals
-}  // namespace ArduinoJson
+}  // namespace ARDUINOJSON_NAMESPACE
diff --git a/src/ArduinoJson/Strings/ZeroTerminatedRamString.hpp b/src/ArduinoJson/Strings/ZeroTerminatedRamString.hpp
index c5ed8926..79f11330 100644
--- a/src/ArduinoJson/Strings/ZeroTerminatedRamString.hpp
+++ b/src/ArduinoJson/Strings/ZeroTerminatedRamString.hpp
@@ -4,8 +4,7 @@
 
 #pragma once
 
-namespace ArduinoJson {
-namespace Internals {
+namespace ARDUINOJSON_NAMESPACE {
 
 class ZeroTerminatedRamString {
  public:
@@ -49,5 +48,4 @@ struct IsString<TChar*> {
   static const bool value = sizeof(TChar) == 1;
 };
 
-}  // namespace Internals
-}  // namespace ArduinoJson
+}  // namespace ARDUINOJSON_NAMESPACE
diff --git a/test/CMakeLists.txt b/test/CMakeLists.txt
index 38fbd05a..8b96326f 100644
--- a/test/CMakeLists.txt
+++ b/test/CMakeLists.txt
@@ -85,3 +85,4 @@ add_subdirectory(MsgPackDeserializer)
 add_subdirectory(MsgPackSerializer)
 add_subdirectory(Numbers)
 add_subdirectory(StaticMemoryPool)
+add_subdirectory(MixedConfiguration)
diff --git a/test/DynamicMemoryPool/alloc.cpp b/test/DynamicMemoryPool/alloc.cpp
index bd7aaa31..aa444d64 100644
--- a/test/DynamicMemoryPool/alloc.cpp
+++ b/test/DynamicMemoryPool/alloc.cpp
@@ -6,7 +6,7 @@
 #include <catch.hpp>
 #include <sstream>
 
-using namespace ArduinoJson::Internals;
+using namespace ARDUINOJSON_NAMESPACE;
 
 static bool isAligned(void* ptr) {
   const size_t mask = sizeof(void*) - 1;
diff --git a/test/DynamicMemoryPool/no_memory.cpp b/test/DynamicMemoryPool/no_memory.cpp
index fb775443..6df934be 100644
--- a/test/DynamicMemoryPool/no_memory.cpp
+++ b/test/DynamicMemoryPool/no_memory.cpp
@@ -5,7 +5,7 @@
 #include <ArduinoJson.h>
 #include <catch.hpp>
 
-using namespace ArduinoJson::Internals;
+using namespace ARDUINOJSON_NAMESPACE;
 
 struct NoMemoryAllocator {
   void* allocate(size_t) {
diff --git a/test/DynamicMemoryPool/size.cpp b/test/DynamicMemoryPool/size.cpp
index d9c28fce..e6938f17 100644
--- a/test/DynamicMemoryPool/size.cpp
+++ b/test/DynamicMemoryPool/size.cpp
@@ -5,7 +5,7 @@
 #include <ArduinoJson/Memory/DynamicMemoryPool.hpp>
 #include <catch.hpp>
 
-using namespace ArduinoJson::Internals;
+using namespace ARDUINOJSON_NAMESPACE;
 
 TEST_CASE("DynamicMemoryPool::size()") {
   DynamicMemoryPool memoryPool;
diff --git a/test/DynamicMemoryPool/startString.cpp b/test/DynamicMemoryPool/startString.cpp
index 53237bd1..43e600b9 100644
--- a/test/DynamicMemoryPool/startString.cpp
+++ b/test/DynamicMemoryPool/startString.cpp
@@ -5,7 +5,7 @@
 #include <ArduinoJson/Memory/DynamicMemoryPool.hpp>
 #include <catch.hpp>
 
-using namespace ArduinoJson::Internals;
+using namespace ARDUINOJSON_NAMESPACE;
 
 TEST_CASE("DynamicMemoryPool::startString()") {
   SECTION("WorksWhenBufferIsBigEnough") {
diff --git a/test/JsonArray/subscript.cpp b/test/JsonArray/subscript.cpp
index 920d494c..f70f4c93 100644
--- a/test/JsonArray/subscript.cpp
+++ b/test/JsonArray/subscript.cpp
@@ -18,10 +18,10 @@ TEST_CASE("JsonArray::operator[]") {
     REQUIRE(false == array[0].is<bool>());
   }
 
-#if ARDUINOJSON_USE_LONG_LONG || ARDUINOJSON_USE_INT64
+#if ARDUINOJSON_USE_LONG_LONG
   SECTION("long long") {
     array[0] = 9223372036854775807;
-    REQUIRE(9223372036854775807 == array[0].as<long long>());
+    REQUIRE(9223372036854775807 == array[0].as<int64_t>());
     REQUIRE(true == array[0].is<int>());
     REQUIRE(false == array[0].is<bool>());
   }
diff --git a/test/JsonDeserializer/deserializeJsonValue.cpp b/test/JsonDeserializer/deserializeJsonValue.cpp
index c21ee327..f818d69b 100644
--- a/test/JsonDeserializer/deserializeJsonValue.cpp
+++ b/test/JsonDeserializer/deserializeJsonValue.cpp
@@ -7,6 +7,11 @@
 
 using namespace Catch::Matchers;
 
+namespace my {
+using ARDUINOJSON_NAMESPACE::isinf;
+using ARDUINOJSON_NAMESPACE::isnan;
+}
+
 TEST_CASE("deserializeJson(DynamicJsonDocument&)") {
   DynamicJsonDocument doc;
 
@@ -99,28 +104,28 @@ TEST_CASE("deserializeJson(DynamicJsonDocument&)") {
     DeserializationError err = deserializeJson(doc, "NaN");
     REQUIRE(err == DeserializationError::Ok);
     REQUIRE(doc.is<float>() == true);
-    REQUIRE(Internals::isnan(doc.as<float>()));
+    REQUIRE(my::isnan(doc.as<float>()));
   }
 
   SECTION("Infinity") {
     DeserializationError err = deserializeJson(doc, "Infinity");
     REQUIRE(err == DeserializationError::Ok);
     REQUIRE(doc.is<float>() == true);
-    REQUIRE(Internals::isinf(doc.as<float>()));
+    REQUIRE(my::isinf(doc.as<float>()));
   }
 
   SECTION("+Infinity") {
     DeserializationError err = deserializeJson(doc, "+Infinity");
     REQUIRE(err == DeserializationError::Ok);
     REQUIRE(doc.is<float>() == true);
-    REQUIRE(Internals::isinf(doc.as<float>()));
+    REQUIRE(my::isinf(doc.as<float>()));
   }
 
   SECTION("-Infinity") {
     DeserializationError err = deserializeJson(doc, "-Infinity");
     REQUIRE(err == DeserializationError::Ok);
     REQUIRE(doc.is<float>() == true);
-    REQUIRE(Internals::isinf(doc.as<float>()));
+    REQUIRE(my::isinf(doc.as<float>()));
   }
 
   SECTION("issue #628") {
diff --git a/test/JsonSerializer/JsonVariant.cpp b/test/JsonSerializer/JsonVariant.cpp
index b2287d77..3dc8003d 100644
--- a/test/JsonSerializer/JsonVariant.cpp
+++ b/test/JsonSerializer/JsonVariant.cpp
@@ -69,7 +69,7 @@ TEST_CASE("serializeJson(JsonVariant)") {
     check(false, "false");
   }
 
-#if ARDUINOJSON_USE_LONG_LONG || ARDUINOJSON_USE_INT64
+#if ARDUINOJSON_USE_LONG_LONG
   SECTION("NegativeInt64") {
     check(-9223372036854775807 - 1, "-9223372036854775808");
   }
diff --git a/test/JsonVariant/as.cpp b/test/JsonVariant/as.cpp
index d2dac203..e2e37552 100644
--- a/test/JsonVariant/as.cpp
+++ b/test/JsonVariant/as.cpp
@@ -147,7 +147,7 @@ TEST_CASE("JsonVariant::as()") {
     }
   }
 
-#if ARDUINOJSON_USE_LONG_LONG || ARDUINOJSON_USE_INT64
+#if ARDUINOJSON_USE_LONG_LONG
   SECTION("Smallest int64 negative") {
     variant.set("-9223372036854775808");
     REQUIRE(variant.as<long long>() == -9223372036854775807 - 1);
diff --git a/test/JsonVariant/set_get.cpp b/test/JsonVariant/set_get.cpp
index 05982079..dd181d8a 100644
--- a/test/JsonVariant/set_get.cpp
+++ b/test/JsonVariant/set_get.cpp
@@ -39,9 +39,9 @@ void checkNumericType() {
 }
 
 TEST_CASE("JsonVariant set()/get()") {
-#if ARDUINOJSON_USE_LONG_LONG || ARDUINOJSON_USE_INT64
+#if ARDUINOJSON_USE_LONG_LONG
   SECTION("SizeOfJsonInteger") {
-    REQUIRE(8 == sizeof(Internals::JsonInteger));
+    REQUIRE(8 == sizeof(JsonInteger));
   }
 #endif
 
@@ -95,7 +95,7 @@ TEST_CASE("JsonVariant set()/get()") {
   SECTION("UShort") {
     checkNumericType<unsigned short>();
   }
-#if ARDUINOJSON_USE_LONG_LONG || ARDUINOJSON_USE_INT64
+#if ARDUINOJSON_USE_LONG_LONG
   SECTION("LongLong") {
     checkNumericType<unsigned long long>();
   }
@@ -122,7 +122,7 @@ TEST_CASE("JsonVariant set()/get()") {
   SECTION("Uint32") {
     checkNumericType<uint32_t>();
   }
-#if ARDUINOJSON_USE_LONG_LONG || ARDUINOJSON_USE_INT64
+#if ARDUINOJSON_USE_LONG_LONG
   SECTION("Int64") {
     checkNumericType<int64_t>();
   }
diff --git a/test/JsonWriter/writeFloat.cpp b/test/JsonWriter/writeFloat.cpp
index 90cc0285..e71854a4 100644
--- a/test/JsonWriter/writeFloat.cpp
+++ b/test/JsonWriter/writeFloat.cpp
@@ -9,7 +9,7 @@
 #include <ArduinoJson/Json/JsonWriter.hpp>
 #include <ArduinoJson/Serialization/DynamicStringWriter.hpp>
 
-using namespace ArduinoJson::Internals;
+using namespace ARDUINOJSON_NAMESPACE;
 
 template <typename TFloat>
 void check(TFloat input, const std::string& expected) {
diff --git a/test/JsonWriter/writeString.cpp b/test/JsonWriter/writeString.cpp
index 0970fa2b..ce2d398d 100644
--- a/test/JsonWriter/writeString.cpp
+++ b/test/JsonWriter/writeString.cpp
@@ -7,7 +7,7 @@
 #include <ArduinoJson/Json/JsonWriter.hpp>
 #include <ArduinoJson/Serialization/StaticStringWriter.hpp>
 
-using namespace ArduinoJson::Internals;
+using namespace ARDUINOJSON_NAMESPACE;
 
 void check(const char* input, std::string expected) {
   char output[1024];
diff --git a/test/Misc/FloatParts.cpp b/test/Misc/FloatParts.cpp
index f3e10a74..bb7efced 100644
--- a/test/Misc/FloatParts.cpp
+++ b/test/Misc/FloatParts.cpp
@@ -5,7 +5,7 @@
 #include <ArduinoJson/Numbers/FloatParts.hpp>
 #include <catch.hpp>
 
-using namespace ArduinoJson::Internals;
+using namespace ARDUINOJSON_NAMESPACE;
 
 TEST_CASE("FloatParts<double>") {
   SECTION("1.7976931348623157E+308") {
diff --git a/test/Misc/StringWriter.cpp b/test/Misc/StringWriter.cpp
index df4ffe2b..10af1fc2 100644
--- a/test/Misc/StringWriter.cpp
+++ b/test/Misc/StringWriter.cpp
@@ -5,7 +5,7 @@
 #include <ArduinoJson.h>
 #include <catch.hpp>
 
-using namespace ArduinoJson::Internals;
+using namespace ARDUINOJSON_NAMESPACE;
 
 template <typename StringWriter>
 static size_t print(StringWriter& sb, const char* s) {
diff --git a/test/Misc/TypeTraits.cpp b/test/Misc/TypeTraits.cpp
index 41cdebbc..32a64b8b 100644
--- a/test/Misc/TypeTraits.cpp
+++ b/test/Misc/TypeTraits.cpp
@@ -5,7 +5,7 @@
 #include <ArduinoJson.h>
 #include <catch.hpp>
 
-using namespace ArduinoJson::Internals;
+using namespace ARDUINOJSON_NAMESPACE;
 
 TEST_CASE("Polyfills/type_traits") {
   SECTION("is_base_of") {
diff --git a/test/MixedConfiguration/CMakeLists.txt b/test/MixedConfiguration/CMakeLists.txt
new file mode 100644
index 00000000..4dc1a113
--- /dev/null
+++ b/test/MixedConfiguration/CMakeLists.txt
@@ -0,0 +1,16 @@
+# ArduinoJson - arduinojson.org
+# Copyright Benoit Blanchon 2014-2018
+# MIT License
+
+# we need C++11 for 'long long'
+set(CMAKE_CXX_STANDARD 11)
+
+add_executable(MixedConfigurationTests
+	use_double_0.cpp
+	use_double_1.cpp
+	use_long_long_0.cpp
+	use_long_long_1.cpp
+)
+
+target_link_libraries(MixedConfigurationTests catch)
+add_test(MixedConfiguration MixedConfigurationTests)
diff --git a/test/MixedConfiguration/use_double_0.cpp b/test/MixedConfiguration/use_double_0.cpp
new file mode 100644
index 00000000..9f369582
--- /dev/null
+++ b/test/MixedConfiguration/use_double_0.cpp
@@ -0,0 +1,17 @@
+#define ARDUINOJSON_USE_DOUBLE 0
+#include <ArduinoJson.h>
+
+#include <catch.hpp>
+
+TEST_CASE("ARDUINOJSON_USE_DOUBLE == 0") {
+  DynamicJsonDocument doc;
+  JsonObject root = doc.to<JsonObject>();
+
+  root["pi"] = 3.14;
+  root["e"] = 2.72;
+
+  std::string json;
+  serializeJson(doc, json);
+
+  REQUIRE(json == "{\"pi\":3.14,\"e\":2.72}");
+}
diff --git a/test/MixedConfiguration/use_double_1.cpp b/test/MixedConfiguration/use_double_1.cpp
new file mode 100644
index 00000000..e027a0f9
--- /dev/null
+++ b/test/MixedConfiguration/use_double_1.cpp
@@ -0,0 +1,17 @@
+#define ARDUINOJSON_USE_DOUBLE 1
+#include <ArduinoJson.h>
+
+#include <catch.hpp>
+
+TEST_CASE("ARDUINOJSON_USE_DOUBLE == 1") {
+  DynamicJsonDocument doc;
+  JsonObject root = doc.to<JsonObject>();
+
+  root["pi"] = 3.14;
+  root["e"] = 2.72;
+
+  std::string json;
+  serializeJson(doc, json);
+
+  REQUIRE(json == "{\"pi\":3.14,\"e\":2.72}");
+}
diff --git a/test/MixedConfiguration/use_long_long_0.cpp b/test/MixedConfiguration/use_long_long_0.cpp
new file mode 100644
index 00000000..f9267275
--- /dev/null
+++ b/test/MixedConfiguration/use_long_long_0.cpp
@@ -0,0 +1,30 @@
+#define ARDUINOJSON_USE_LONG_LONG 0
+#include <ArduinoJson.h>
+
+#include <catch.hpp>
+
+template <size_t size_of_long>
+std::string get_expected_json();
+
+template <>
+std::string get_expected_json<4>() {
+  return "{\"A\":2899336981,\"B\":2129924785}";
+}
+
+template <>
+std::string get_expected_json<8>() {
+  return "{\"A\":123456789123456789,\"B\":987654321987654321}";
+}
+
+TEST_CASE("ARDUINOJSON_USE_LONG_LONG == 0") {
+  DynamicJsonDocument doc;
+  JsonObject root = doc.to<JsonObject>();
+
+  root["A"] = 123456789123456789;
+  root["B"] = 987654321987654321;
+
+  std::string json;
+  serializeJson(doc, json);
+
+  REQUIRE(json == get_expected_json<sizeof(long)>());
+}
diff --git a/test/MixedConfiguration/use_long_long_1.cpp b/test/MixedConfiguration/use_long_long_1.cpp
new file mode 100644
index 00000000..6050ed3c
--- /dev/null
+++ b/test/MixedConfiguration/use_long_long_1.cpp
@@ -0,0 +1,17 @@
+#define ARDUINOJSON_USE_LONG_LONG 1
+#include <ArduinoJson.h>
+
+#include <catch.hpp>
+
+TEST_CASE("ARDUINOJSON_USE_LONG_LONG == 1") {
+  DynamicJsonDocument doc;
+  JsonObject root = doc.to<JsonObject>();
+
+  root["A"] = 123456789123456789;
+  root["B"] = 987654321987654321;
+
+  std::string json;
+  serializeJson(doc, json);
+
+  REQUIRE(json == "{\"A\":123456789123456789,\"B\":987654321987654321}");
+}
diff --git a/test/MsgPackDeserializer/deserializeVariant.cpp b/test/MsgPackDeserializer/deserializeVariant.cpp
index f63f964e..c9b6f27f 100644
--- a/test/MsgPackDeserializer/deserializeVariant.cpp
+++ b/test/MsgPackDeserializer/deserializeVariant.cpp
@@ -63,7 +63,7 @@ TEST_CASE("deserialize MsgPack value") {
   }
 
   SECTION("uint 64") {
-#if ARDUINOJSON_USE_LONG_LONG || ARDUINOJSON_USE_INT64
+#if ARDUINOJSON_USE_LONG_LONG
     check<uint64_t>("\xCF\x00\x00\x00\x00\x00\x00\x00\x00", 0U);
     check<uint64_t>("\xCF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF",
                     0xFFFFFFFFFFFFFFFFU);
@@ -94,7 +94,7 @@ TEST_CASE("deserialize MsgPack value") {
   }
 
   SECTION("int 64") {
-#if ARDUINOJSON_USE_LONG_LONG || ARDUINOJSON_USE_INT64
+#if ARDUINOJSON_USE_LONG_LONG
     check<uint64_t>("\xD3\x00\x00\x00\x00\x00\x00\x00\x00", 0U);
     check<uint64_t>("\xD3\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF",
                     0xFFFFFFFFFFFFFFFFU);
diff --git a/test/MsgPackDeserializer/doubleToFloat.cpp b/test/MsgPackDeserializer/doubleToFloat.cpp
index da37bd56..e7fea8d5 100644
--- a/test/MsgPackDeserializer/doubleToFloat.cpp
+++ b/test/MsgPackDeserializer/doubleToFloat.cpp
@@ -5,7 +5,7 @@
 #include <ArduinoJson.h>
 #include <catch.hpp>
 
-using namespace ArduinoJson::Internals;
+using namespace ARDUINOJSON_NAMESPACE;
 
 template <typename T>
 static void check(const char* input, T expected) {
@@ -17,7 +17,7 @@ static void check(const char* input, T expected) {
   CHECK(actual == expected);
 }
 
-TEST_CASE("Internals::doubleToFloat()") {
+TEST_CASE("doubleToFloat()") {
   check("\x40\x09\x21\xCA\xC0\x83\x12\x6F", 3.1415f);
   check("\x00\x00\x00\x00\x00\x00\x00\x00", 0.0f);
   check("\x80\x00\x00\x00\x00\x00\x00\x00", -0.0f);
diff --git a/test/MsgPackSerializer/serializeVariant.cpp b/test/MsgPackSerializer/serializeVariant.cpp
index 952daa53..a9979402 100644
--- a/test/MsgPackSerializer/serializeVariant.cpp
+++ b/test/MsgPackSerializer/serializeVariant.cpp
@@ -65,7 +65,7 @@ TEST_CASE("serialize MsgPack value") {
     check(0xFFFFFFFFU, "\xCE\xFF\xFF\xFF\xFF");
   }
 
-#if ARDUINOJSON_USE_LONG_LONG || ARDUINOJSON_USE_INT64
+#if ARDUINOJSON_USE_LONG_LONG
   SECTION("uint 64") {
     check(0x0001000000000000U, "\xCF\x00\x01\x00\x00\x00\x00\x00\x00");
     check(0x123456789ABCDEF0U, "\xCF\x12\x34\x56\x78\x9A\xBC\xDE\xF0");
@@ -93,7 +93,7 @@ TEST_CASE("serialize MsgPack value") {
     check(-2147483647 - 1, "\xD2\x80\x00\x00\x00");
   }
 
-#if ARDUINOJSON_USE_LONG_LONG || ARDUINOJSON_USE_INT64
+#if ARDUINOJSON_USE_LONG_LONG
   SECTION("int 64") {
     check(int64_t(0xFEDCBA9876543210), "\xD3\xFE\xDC\xBA\x98\x76\x54\x32\x10");
   }
diff --git a/test/Numbers/isFloat.cpp b/test/Numbers/isFloat.cpp
index 3edce987..192b7f91 100644
--- a/test/Numbers/isFloat.cpp
+++ b/test/Numbers/isFloat.cpp
@@ -5,7 +5,7 @@
 #include <ArduinoJson/Numbers/isFloat.hpp>
 #include <catch.hpp>
 
-using namespace ArduinoJson::Internals;
+using namespace ARDUINOJSON_NAMESPACE;
 
 TEST_CASE("isFloat()") {
   SECTION("Input is NULL") {
diff --git a/test/Numbers/isInteger.cpp b/test/Numbers/isInteger.cpp
index 650d37c0..4f95a2e8 100644
--- a/test/Numbers/isInteger.cpp
+++ b/test/Numbers/isInteger.cpp
@@ -5,7 +5,7 @@
 #include <ArduinoJson/Numbers/isInteger.hpp>
 #include <catch.hpp>
 
-using namespace ArduinoJson::Internals;
+using namespace ARDUINOJSON_NAMESPACE;
 
 TEST_CASE("isInteger()") {
   SECTION("Null") {
diff --git a/test/Numbers/parseFloat.cpp b/test/Numbers/parseFloat.cpp
index 18cb0cfb..8628a78d 100644
--- a/test/Numbers/parseFloat.cpp
+++ b/test/Numbers/parseFloat.cpp
@@ -5,7 +5,7 @@
 #include <ArduinoJson/Numbers/parseFloat.hpp>
 #include <catch.hpp>
 
-using namespace ArduinoJson::Internals;
+using namespace ARDUINOJSON_NAMESPACE;
 
 template <typename T>
 void check(const char* input, T expected) {
diff --git a/test/Numbers/parseInteger.cpp b/test/Numbers/parseInteger.cpp
index 786834b1..1b945168 100644
--- a/test/Numbers/parseInteger.cpp
+++ b/test/Numbers/parseInteger.cpp
@@ -6,7 +6,7 @@
 #include <ArduinoJson/Numbers/parseInteger.hpp>
 #include <catch.hpp>
 
-using namespace ArduinoJson::Internals;
+using namespace ARDUINOJSON_NAMESPACE;
 
 template <typename T>
 void check(const char* input, T expected) {
diff --git a/test/StaticMemoryPool/alloc.cpp b/test/StaticMemoryPool/alloc.cpp
index 0671cad4..23500e22 100644
--- a/test/StaticMemoryPool/alloc.cpp
+++ b/test/StaticMemoryPool/alloc.cpp
@@ -5,7 +5,7 @@
 #include <ArduinoJson/Memory/StaticMemoryPool.hpp>
 #include <catch.hpp>
 
-using namespace ArduinoJson::Internals;
+using namespace ARDUINOJSON_NAMESPACE;
 
 static bool isAligned(void *ptr) {
   const size_t mask = sizeof(void *) - 1;
diff --git a/test/StaticMemoryPool/size.cpp b/test/StaticMemoryPool/size.cpp
index a3af0d1f..411d432b 100644
--- a/test/StaticMemoryPool/size.cpp
+++ b/test/StaticMemoryPool/size.cpp
@@ -5,7 +5,7 @@
 #include <ArduinoJson/Memory/StaticMemoryPool.hpp>
 #include <catch.hpp>
 
-using namespace ArduinoJson::Internals;
+using namespace ARDUINOJSON_NAMESPACE;
 
 TEST_CASE("StaticMemoryPool::size()") {
   StaticMemoryPool<64> memoryPool;
diff --git a/test/StaticMemoryPool/startString.cpp b/test/StaticMemoryPool/startString.cpp
index c8e570fc..b8993097 100644
--- a/test/StaticMemoryPool/startString.cpp
+++ b/test/StaticMemoryPool/startString.cpp
@@ -5,7 +5,7 @@
 #include <ArduinoJson.h>
 #include <catch.hpp>
 
-using namespace ArduinoJson::Internals;
+using namespace ARDUINOJSON_NAMESPACE;
 
 TEST_CASE("StaticMemoryPool::startString()") {
   SECTION("WorksWhenBufferIsBigEnough") {