diff --git a/CHANGELOG.md b/CHANGELOG.md
index 62dbdf4b..09933380 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -6,6 +6,7 @@ HEAD
 
 * Changed the rules of string duplication (issue #658)
 * Changed the return type of `strdup()` to `const char*` to prevent double duplication
+* Marked `strdup()` as deprecated
 
 > ### New rules for string duplication
 >
diff --git a/src/ArduinoJson/JsonBuffer.hpp b/src/ArduinoJson/JsonBuffer.hpp
index 36775cb1..192d8b38 100644
--- a/src/ArduinoJson/JsonBuffer.hpp
+++ b/src/ArduinoJson/JsonBuffer.hpp
@@ -41,17 +41,18 @@ class JsonBuffer : Internals::NonCopyable {
   // const char* strdup(TValue);
   // TValue = const std::string&, const String&,
   template <typename TString>
+  DEPRECATED("char* are duplicated, you don't need strdup() anymore")
   typename TypeTraits::EnableIf<!TypeTraits::IsArray<TString>::value,
-                                const char *>::type
-  strdup(const TString &src) {
+                                const char *>::type strdup(const TString &src) {
     return Internals::StringTraits<TString>::duplicate(src, this);
   }
   //
   // const char* strdup(TValue);
-  // TValue = const char*, const char[N], const FlashStringHelper*
+  // TValue = char*, const char*, const FlashStringHelper*
   template <typename TString>
-  const char *strdup(const TString *src) {
-    return Internals::StringTraits<const TString *>::duplicate(src, this);
+  DEPRECATED("char* are duplicated, you don't need strdup() anymore")
+  const char *strdup(TString *src) {
+    return Internals::StringTraits<TString *>::duplicate(src, this);
   }
 
   // Allocates n bytes in the JsonBuffer.
diff --git a/test/DynamicJsonBuffer/CMakeLists.txt b/test/DynamicJsonBuffer/CMakeLists.txt
index f028ccc4..9030f376 100644
--- a/test/DynamicJsonBuffer/CMakeLists.txt
+++ b/test/DynamicJsonBuffer/CMakeLists.txt
@@ -9,7 +9,6 @@ add_executable(DynamicJsonBufferTests
 	no_memory.cpp
 	size.cpp
 	startString.cpp
-	strdup.cpp
 )
 
 target_link_libraries(DynamicJsonBufferTests catch)
diff --git a/test/DynamicJsonBuffer/strdup.cpp b/test/DynamicJsonBuffer/strdup.cpp
deleted file mode 100644
index f6fb3b1c..00000000
--- a/test/DynamicJsonBuffer/strdup.cpp
+++ /dev/null
@@ -1,23 +0,0 @@
-// ArduinoJson - arduinojson.org
-// Copyright Benoit Blanchon 2014-2018
-// MIT License
-
-#include <ArduinoJson.h>
-#include <catch.hpp>
-
-TEST_CASE("DynamicJsonBuffer::strdup()") {
-  DynamicJsonBuffer buffer;
-
-  SECTION("Should return a copy") {
-    char original[] = "hello";
-    const char* copy = buffer.strdup(original);
-    strcpy(original, "world");
-    REQUIRE(std::string("hello") == copy);
-  }
-
-  SECTION("Given NULL, return NULL") {
-    const char* original = NULL;
-    const char* copy = buffer.strdup(original);
-    REQUIRE(0 == copy);
-  }
-}
diff --git a/test/Misc/deprecated.cpp b/test/Misc/deprecated.cpp
index bc7f97ba..8fa4fe28 100644
--- a/test/Misc/deprecated.cpp
+++ b/test/Misc/deprecated.cpp
@@ -104,3 +104,37 @@ TEST_CASE("Deprecated functions") {
     REQUIRE(123.45 == obj["hello"].as<double>());
   }
 }
+
+TEST_CASE("DynamicJsonBuffer::strdup()") {
+  DynamicJsonBuffer buffer;
+
+  SECTION("char*") {
+    char original[] = "hello";
+    const char* copy = buffer.strdup(original);
+    strcpy(original, "world");
+    REQUIRE(std::string("hello") == copy);
+  }
+
+  SECTION("unsigned char*") {
+    unsigned char value[] = "world";
+
+    DynamicJsonBuffer jsonBuffer;
+    const char* dup = jsonBuffer.strdup(value);
+
+    REQUIRE(static_cast<const void*>(value) != static_cast<const void*>(dup));
+    REQUIRE(std::string("world") == dup);
+  }
+
+  SECTION("std::string") {
+    std::string original("hello");
+    const char* copy = buffer.strdup(original);
+    original[0] = 'w';
+    REQUIRE(std::string("hello") == copy);
+  }
+
+  SECTION("NULL") {
+    const char* original = NULL;
+    const char* copy = buffer.strdup(original);
+    REQUIRE(0 == copy);
+  }
+}
diff --git a/test/Misc/std_string.cpp b/test/Misc/std_string.cpp
index 2cfa3a3c..aeb188dd 100644
--- a/test/Misc/std_string.cpp
+++ b/test/Misc/std_string.cpp
@@ -240,11 +240,4 @@ TEST_CASE("std::string") {
 
     REQUIRE(sizeBefore == sizeAfter);
   }
-
-  SECTION("JsonBuffer_strdup") {
-    std::string original("hello");
-    const char *copy = jb.strdup(original);
-    original[0] = 'w';
-    REQUIRE(std::string("hello") == copy);
-  }
 }
diff --git a/test/Misc/unsigned_char.cpp b/test/Misc/unsigned_char.cpp
index 5d7a47e0..ce1c474a 100644
--- a/test/Misc/unsigned_char.cpp
+++ b/test/Misc/unsigned_char.cpp
@@ -259,14 +259,4 @@ TEST_CASE("unsigned char string") {
 
     REQUIRE(std::string("world") == arr[0]);
   }
-
-  SECTION("JsonBuffer::strdup()") {
-    unsigned char value[] = "world";
-
-    DynamicJsonBuffer jsonBuffer;
-    const char* dup = jsonBuffer.strdup(value);
-
-    REQUIRE(static_cast<const void*>(value) != static_cast<const void*>(dup));
-    REQUIRE(std::string("world") == dup);
-  }
 }
diff --git a/test/Misc/vla.cpp b/test/Misc/vla.cpp
index 1e5ee1e2..e9d1cb67 100644
--- a/test/Misc/vla.cpp
+++ b/test/Misc/vla.cpp
@@ -327,17 +327,5 @@ TEST_CASE("Variable Length Array") {
 
     REQUIRE(std::string("world") == arr[0]);
   }
-
-  SECTION("JsonBuffer_strdup") {
-    int i = 16;
-    char vla[i];
-    strcpy(vla, "world");
-
-    DynamicJsonBuffer jsonBuffer;
-    const char* dup = jsonBuffer.strdup(vla);
-
-    REQUIRE(static_cast<const void*>(vla) != static_cast<const void*>(dup));
-    REQUIRE(std::string("world") == dup);
-  }
 }
 #endif