diff --git a/CHANGELOG.md b/CHANGELOG.md
index f49c949d..d67a779e 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,6 +1,11 @@
 ArduinoJson: change log
 =======================
 
+HEAD
+----
+
+* Fix `call of overloaded 'String(const char*, int)' is ambiguous`
+
 v6.19.2 (2022-02-14)
 -------
 
diff --git a/extras/tests/JsonObject/subscript.cpp b/extras/tests/JsonObject/subscript.cpp
index b5792491..aa7dde35 100644
--- a/extras/tests/JsonObject/subscript.cpp
+++ b/extras/tests/JsonObject/subscript.cpp
@@ -141,13 +141,13 @@ TEST_CASE("JsonObject::operator[]") {
   }
 
   SECTION("should duplicate a non-static JsonString key") {
-    obj[JsonString("hello", false)] = "world";
+    obj[JsonString("hello", JsonString::Copied)] = "world";
     const size_t expectedSize = JSON_OBJECT_SIZE(1) + JSON_STRING_SIZE(5);
     REQUIRE(expectedSize == doc.memoryUsage());
   }
 
   SECTION("should not duplicate a static JsonString key") {
-    obj[JsonString("hello", true)] = "world";
+    obj[JsonString("hello", JsonString::Linked)] = "world";
     const size_t expectedSize = JSON_OBJECT_SIZE(1);
     REQUIRE(expectedSize == doc.memoryUsage());
   }
diff --git a/extras/tests/JsonVariant/as.cpp b/extras/tests/JsonVariant/as.cpp
index 455b8d81..c9956778 100644
--- a/extras/tests/JsonVariant/as.cpp
+++ b/extras/tests/JsonVariant/as.cpp
@@ -136,7 +136,7 @@ TEST_CASE("JsonVariant::as()") {
 
     REQUIRE(variant.as<long>() == 42L);
     REQUIRE(variant.as<JsonString>() == "42");
-    REQUIRE(variant.as<JsonString>().isStatic() == true);
+    REQUIRE(variant.as<JsonString>().isLinked() == true);
   }
 
   SECTION("set(\"hello\")") {
@@ -159,7 +159,7 @@ TEST_CASE("JsonVariant::as()") {
     REQUIRE(variant.as<const char*>() == std::string("4.2"));
     REQUIRE(variant.as<std::string>() == std::string("4.2"));
     REQUIRE(variant.as<JsonString>() == "4.2");
-    REQUIRE(variant.as<JsonString>().isStatic() == false);
+    REQUIRE(variant.as<JsonString>().isLinked() == false);
   }
 
   SECTION("set(\"true\")") {
diff --git a/extras/tests/JsonVariant/set.cpp b/extras/tests/JsonVariant/set.cpp
index f0bfba39..eba15d43 100644
--- a/extras/tests/JsonVariant/set.cpp
+++ b/extras/tests/JsonVariant/set.cpp
@@ -98,7 +98,7 @@ TEST_CASE("JsonVariant::set() when there is enough memory") {
     char str[16];
 
     strcpy(str, "hello");
-    bool result = variant.set(JsonString(str, true));
+    bool result = variant.set(JsonString(str, JsonString::Linked));
     strcpy(str, "world");
 
     REQUIRE(result == true);
@@ -109,7 +109,7 @@ TEST_CASE("JsonVariant::set() when there is enough memory") {
     char str[16];
 
     strcpy(str, "hello");
-    bool result = variant.set(JsonString(str, false));
+    bool result = variant.set(JsonString(str, JsonString::Copied));
     strcpy(str, "world");
 
     REQUIRE(result == true);
diff --git a/extras/tests/Misc/JsonString.cpp b/extras/tests/Misc/JsonString.cpp
index 10d08d36..b7d606fd 100644
--- a/extras/tests/Misc/JsonString.cpp
+++ b/extras/tests/Misc/JsonString.cpp
@@ -13,7 +13,7 @@ TEST_CASE("JsonString") {
 
     CHECK(s.isNull() == true);
     CHECK(s.c_str() == 0);
-    CHECK(s.isStatic() == true);
+    CHECK(s.isLinked() == true);
   }
 
   SECTION("Compare null with boolean") {
@@ -82,4 +82,11 @@ TEST_CASE("JsonString") {
     ss << JsonString("hello world!");
     CHECK(ss.str() == "hello world!");
   }
+
+  SECTION("Construct with a size") {
+    JsonString s("hello world", 5);
+
+    CHECK(s.size() == 5);
+    CHECK(s.isLinked() == true);
+  }
 }
diff --git a/src/ArduinoJson/Collection/CollectionImpl.hpp b/src/ArduinoJson/Collection/CollectionImpl.hpp
index 60f5cb11..35678eeb 100644
--- a/src/ArduinoJson/Collection/CollectionImpl.hpp
+++ b/src/ArduinoJson/Collection/CollectionImpl.hpp
@@ -64,7 +64,7 @@ inline bool CollectionData::copyFrom(const CollectionData& src,
   for (VariantSlot* s = src._head; s; s = s->next()) {
     VariantData* var;
     if (s->key() != 0) {
-      String key(s->key(), !s->ownsKey());
+      String key(s->key(), s->ownsKey() ? String::Copied : String::Linked);
       var = addMember(adaptString(key), pool, getStringStoragePolicy(key));
     } else {
       var = addElement(pool);
diff --git a/src/ArduinoJson/Object/Pair.hpp b/src/ArduinoJson/Object/Pair.hpp
index e9e71eb6..7e3ca32c 100644
--- a/src/ArduinoJson/Object/Pair.hpp
+++ b/src/ArduinoJson/Object/Pair.hpp
@@ -13,7 +13,8 @@ class Pair {
  public:
   Pair(MemoryPool* pool, VariantSlot* slot) {
     if (slot) {
-      _key = String(slot->key(), !slot->ownsKey());
+      _key = String(slot->key(),
+                    slot->ownsKey() ? String::Copied : String::Linked);
       _value = VariantRef(pool, slot->data());
     }
   }
@@ -35,7 +36,8 @@ class PairConst {
  public:
   PairConst(const VariantSlot* slot) {
     if (slot) {
-      _key = String(slot->key(), !slot->ownsKey());
+      _key = String(slot->key(),
+                    slot->ownsKey() ? String::Copied : String::Linked);
       _value = VariantConstRef(slot->data());
     }
   }
diff --git a/src/ArduinoJson/StringStorage/StringCopier.hpp b/src/ArduinoJson/StringStorage/StringCopier.hpp
index 455a155a..f743e4ac 100644
--- a/src/ArduinoJson/StringStorage/StringCopier.hpp
+++ b/src/ArduinoJson/StringStorage/StringCopier.hpp
@@ -22,7 +22,7 @@ class StringCopier {
   String save() {
     ARDUINOJSON_ASSERT(_ptr);
     ARDUINOJSON_ASSERT(_size < _capacity);  // needs room for the terminator
-    return String(_pool->saveStringFromFreeZone(_size), _size, false);
+    return String(_pool->saveStringFromFreeZone(_size), _size, String::Copied);
   }
 
   void append(const char* s) {
@@ -52,7 +52,7 @@ class StringCopier {
     ARDUINOJSON_ASSERT(_ptr);
     ARDUINOJSON_ASSERT(_size < _capacity);
     _ptr[_size] = 0;
-    return String(_ptr, _size, false);
+    return String(_ptr, _size, String::Copied);
   }
 
  private:
diff --git a/src/ArduinoJson/StringStorage/StringMover.hpp b/src/ArduinoJson/StringStorage/StringMover.hpp
index 4ed7d92e..f4cd1bae 100644
--- a/src/ArduinoJson/StringStorage/StringMover.hpp
+++ b/src/ArduinoJson/StringStorage/StringMover.hpp
@@ -33,7 +33,7 @@ class StringMover {
 
   String str() const {
     _writePtr[0] = 0;  // terminator
-    return String(_startPtr, size(), true);
+    return String(_startPtr, size(), String::Linked);
   }
 
   size_t size() const {
diff --git a/src/ArduinoJson/Strings/StoragePolicy.hpp b/src/ArduinoJson/Strings/StoragePolicy.hpp
index 2a01f0d5..d1e138c4 100644
--- a/src/ArduinoJson/Strings/StoragePolicy.hpp
+++ b/src/ArduinoJson/Strings/StoragePolicy.hpp
@@ -12,7 +12,7 @@ namespace ARDUINOJSON_NAMESPACE {
 struct LinkStringStoragePolicy {
   template <typename TAdaptedString, typename TCallback>
   bool store(TAdaptedString str, MemoryPool *, TCallback callback) {
-    String storedString(str.data(), str.size(), true);
+    String storedString(str.data(), str.size(), String::Linked);
     callback(storedString);
     return !str.isNull();
   }
@@ -50,7 +50,7 @@ inline LinkStringStoragePolicy getStringStoragePolicy(const char *) {
 }
 
 inline LinkOrCopyStringStoragePolicy getStringStoragePolicy(const String &s) {
-  return LinkOrCopyStringStoragePolicy(s.isStatic());
+  return LinkOrCopyStringStoragePolicy(s.isLinked());
 }
 
 }  // namespace ARDUINOJSON_NAMESPACE
diff --git a/src/ArduinoJson/Strings/String.hpp b/src/ArduinoJson/Strings/String.hpp
index 1c71c67a..08956f05 100644
--- a/src/ArduinoJson/Strings/String.hpp
+++ b/src/ArduinoJson/Strings/String.hpp
@@ -14,15 +14,15 @@ namespace ARDUINOJSON_NAMESPACE {
 
 class String : public SafeBoolIdom<String> {
  public:
-  String() : _data(0), _size(0), _isStatic(true) {}
+  enum Ownership { Copied, Linked };
 
-  String(const char* data, bool isStaticData = true)
-      : _data(data),
-        _size(data ? ::strlen(data) : 0),
-        _isStatic(isStaticData) {}
+  String() : _data(0), _size(0), _ownership(Linked) {}
 
-  String(const char* data, size_t sz, bool isStaticData = true)
-      : _data(data), _size(sz), _isStatic(isStaticData) {}
+  String(const char* data, Ownership ownership = Linked)
+      : _data(data), _size(data ? ::strlen(data) : 0), _ownership(ownership) {}
+
+  String(const char* data, size_t sz, Ownership ownership = Linked)
+      : _data(data), _size(sz), _ownership(ownership) {}
 
   const char* c_str() const {
     return _data;
@@ -32,8 +32,8 @@ class String : public SafeBoolIdom<String> {
     return !_data;
   }
 
-  bool isStatic() const {
-    return _isStatic;
+  bool isLinked() const {
+    return _ownership == Linked;
   }
 
   size_t size() const {
@@ -75,7 +75,7 @@ class String : public SafeBoolIdom<String> {
  private:
   const char* _data;
   size_t _size;
-  bool _isStatic;
+  Ownership _ownership;
 };
 
 }  // namespace ARDUINOJSON_NAMESPACE
diff --git a/src/ArduinoJson/Variant/ConverterImpl.hpp b/src/ArduinoJson/Variant/ConverterImpl.hpp
index a825760c..baf1187a 100644
--- a/src/ArduinoJson/Variant/ConverterImpl.hpp
+++ b/src/ArduinoJson/Variant/ConverterImpl.hpp
@@ -208,7 +208,7 @@ class MemoryPoolPrint : public Print {
 
   String str() {
     ARDUINOJSON_ASSERT(_size < _capacity);
-    return String(_pool->saveStringFromFreeZone(_size), _size, false);
+    return String(_pool->saveStringFromFreeZone(_size), _size, String::Copied);
   }
 
   size_t write(uint8_t c) {
diff --git a/src/ArduinoJson/Variant/VariantData.hpp b/src/ArduinoJson/Variant/VariantData.hpp
index 6f807632..27128706 100644
--- a/src/ArduinoJson/Variant/VariantData.hpp
+++ b/src/ArduinoJson/Variant/VariantData.hpp
@@ -210,7 +210,7 @@ class VariantData {
 
   void setString(String s) {
     ARDUINOJSON_ASSERT(s);
-    if (s.isStatic())
+    if (s.isLinked())
       setType(VALUE_IS_LINKED_STRING);
     else
       setType(VALUE_IS_OWNED_STRING);
diff --git a/src/ArduinoJson/Variant/VariantImpl.hpp b/src/ArduinoJson/Variant/VariantImpl.hpp
index bd3ce07b..b5a62087 100644
--- a/src/ArduinoJson/Variant/VariantImpl.hpp
+++ b/src/ArduinoJson/Variant/VariantImpl.hpp
@@ -73,9 +73,11 @@ inline T VariantData::asFloat() const {
 inline String VariantData::asString() const {
   switch (type()) {
     case VALUE_IS_LINKED_STRING:
-      return String(_content.asString.data, _content.asString.size, true);
+      return String(_content.asString.data, _content.asString.size,
+                    String::Linked);
     case VALUE_IS_OWNED_STRING:
-      return String(_content.asString.data, _content.asString.size, false);
+      return String(_content.asString.data, _content.asString.size,
+                    String::Copied);
     default:
       return String();
   }
@@ -174,7 +176,7 @@ template <typename TAdaptedString, typename TCallback>
 bool CopyStringStoragePolicy::store(TAdaptedString str, MemoryPool *pool,
                                     TCallback callback) {
   const char *copy = pool->saveString(str);
-  String storedString(copy, str.size(), false);
+  String storedString(copy, str.size(), String::Copied);
   callback(storedString);
   return copy != 0;
 }
diff --git a/src/ArduinoJson/Variant/VariantSlot.hpp b/src/ArduinoJson/Variant/VariantSlot.hpp
index 8f4169cc..83ff1d78 100644
--- a/src/ArduinoJson/Variant/VariantSlot.hpp
+++ b/src/ArduinoJson/Variant/VariantSlot.hpp
@@ -78,7 +78,7 @@ class VariantSlot {
 
   void setKey(String k) {
     ARDUINOJSON_ASSERT(k);
-    if (k.isStatic())
+    if (k.isLinked())
       _flags &= VALUE_MASK;
     else
       _flags |= OWNED_KEY_BIT;