diff --git a/jerry-core/debugger/debugger.c b/jerry-core/debugger/debugger.c
index bc4c5b9532..06e7c58eac 100644
--- a/jerry-core/debugger/debugger.c
+++ b/jerry-core/debugger/debugger.c
@@ -30,6 +30,15 @@
 #include <unistd.h>
 #endif /* HAVE_TIME_H */
 
+/**
+ * The number of message types in the debugger should reflect the
+ * debugger versioning.
+ */
+JERRY_STATIC_ASSERT (JERRY_DEBUGGER_MESSAGES_OUT_MAX_COUNT == 26
+                     && JERRY_DEBUGGER_MESSAGES_IN_MAX_COUNT == 16
+                     && JERRY_DEBUGGER_VERSION == 1,
+                     debugger_version_correlates_to_message_type_count);
+
 /**
  * Type cast the debugger send buffer into a specific type.
  */
@@ -707,6 +716,7 @@ jerry_debugger_send_configuration (uint8_t max_message_size) /**< maximum messag
   configuration_p->max_message_size = max_message_size;
   configuration_p->cpointer_size = sizeof (jmem_cpointer_t);
   configuration_p->little_endian = (endian_data.uint8_value[0] == 1);
+  configuration_p->version = JERRY_DEBUGGER_VERSION;
 
   return jerry_debugger_send (sizeof (jerry_debugger_send_configuration_t));
 } /* jerry_debugger_send_configuration */
diff --git a/jerry-core/debugger/debugger.h b/jerry-core/debugger/debugger.h
index e4039405e3..404964b9df 100644
--- a/jerry-core/debugger/debugger.h
+++ b/jerry-core/debugger/debugger.h
@@ -23,6 +23,11 @@
 
 /* JerryScript debugger protocol is a simplified version of RFC-6455 (WebSockets). */
 
+/**
+ * JerryScript debugger protocol version.
+ */
+#define JERRY_DEBUGGER_VERSION (1)
+
 /**
  * Frequency of calling jerry_debugger_receive() by the VM.
  */
@@ -125,6 +130,8 @@ typedef enum
   JERRY_DEBUGGER_OUTPUT_RESULT = 24, /**< output sent by the program to the debugger */
   JERRY_DEBUGGER_OUTPUT_RESULT_END = 25, /**< last output result data */
 
+  JERRY_DEBUGGER_MESSAGES_OUT_MAX_COUNT, /**< number of different type of output messages by the debugger */
+
   /* Messages sent by the client to server. */
 
   /* The following messages are accepted in both run and breakpoint modes. */
@@ -147,6 +154,8 @@ typedef enum
   JERRY_DEBUGGER_GET_BACKTRACE = 13, /**< get backtrace */
   JERRY_DEBUGGER_EVAL = 14, /**< first message of evaluating a string */
   JERRY_DEBUGGER_EVAL_PART = 15, /**< next message of evaluating a string */
+
+  JERRY_DEBUGGER_MESSAGES_IN_MAX_COUNT, /**< number of different type of input messages */
 } jerry_debugger_header_type_t;
 
 /**
@@ -189,6 +198,7 @@ typedef struct
   uint8_t max_message_size; /**< maximum incoming message size */
   uint8_t cpointer_size; /**< size of compressed pointers */
   uint8_t little_endian; /**< little endian machine */
+  uint8_t version; /**< debugger version */
 } jerry_debugger_send_configuration_t;
 
 /**
diff --git a/jerry-debugger/jerry-client-ws.html b/jerry-debugger/jerry-client-ws.html
index b2d7548670..f4fe9a87ad 100644
--- a/jerry-debugger/jerry-client-ws.html
+++ b/jerry-debugger/jerry-client-ws.html
@@ -35,6 +35,9 @@ <h2>JerryScript HTML (WebSocket) Debugger Client</h2>
   <div>
 </div>
 <script>
+// Expected JerryScript debugger protocol version
+var JERRY_DEBUGGER_VERSION = 1;
+
 // Messages sent by the server to client.
 var JERRY_DEBUGGER_CONFIGURATION = 1;
 var JERRY_DEBUGGER_PARSE_ERROR = 2;
@@ -136,6 +139,7 @@ <h2>JerryScript HTML (WebSocket) Debugger Client</h2>
   var outputResult = null;
   var exceptionData = null;
   var display = 0;
+  var version = 0;
 
   function assert(expr)
   {
@@ -783,7 +787,7 @@ <h2>JerryScript HTML (WebSocket) Debugger Client</h2>
     if (cpointerSize == 0)
     {
       if (message[0] != JERRY_DEBUGGER_CONFIGURATION
-          || message.byteLength != 4)
+          || message.byteLength != 5)
       {
         abortConnection("the first message must be configuration.");
       }
@@ -792,11 +796,19 @@ <h2>JerryScript HTML (WebSocket) Debugger Client</h2>
       cpointerSize = message[2]
       littleEndian = (message[3] != 0);
 
+      version = message[4];
+
       if (cpointerSize != 2 && cpointerSize != 4)
       {
         abortConnection("compressed pointer must be 2 or 4 byte long.");
       }
 
+      if (version != JERRY_DEBUGGER_VERSION)
+      {
+        abortConnection("incorrect target debugger version detected: "
+                        + version + " expected: " + JERRY_DEBUGGER_VERSION);
+      }
+
       config = false;
       return;
     }
diff --git a/jerry-debugger/jerry-client-ws.py b/jerry-debugger/jerry-client-ws.py
index cfe1eb8ab2..b1b1b9a119 100755
--- a/jerry-debugger/jerry-client-ws.py
+++ b/jerry-debugger/jerry-client-ws.py
@@ -25,6 +25,9 @@
 import struct
 import sys
 
+# Expected debugger protocol version.
+JERRY_DEBUGGER_VERSION = 1
+
 # Messages sent by the server to client.
 JERRY_DEBUGGER_CONFIGURATION = 1
 JERRY_DEBUGGER_PARSE_ERROR = 2
@@ -563,13 +566,14 @@ def __init__(self, address):
         else:
             result = b""
 
-        len_expected = 6
+        len_expected = 7
         # Network configurations, which has the following struct:
         # header [2] - opcode[1], size[1]
         # type [1]
         # max_message_size [1]
         # cpointer_size [1]
         # little_endian [1]
+        # version [1]
 
         while len(result) < len_expected:
             result += self.client_socket.recv(1024)
@@ -578,7 +582,7 @@ def __init__(self, address):
 
         expected = struct.pack("BBB",
                                WEBSOCKET_BINARY_FRAME | WEBSOCKET_FIN_BIT,
-                               4,
+                               5,
                                JERRY_DEBUGGER_CONFIGURATION)
 
         if result[0:3] != expected:
@@ -587,6 +591,12 @@ def __init__(self, address):
         self.max_message_size = ord(result[3])
         self.cp_size = ord(result[4])
         self.little_endian = ord(result[5])
+        self.version = ord(result[6])
+
+        if self.version != JERRY_DEBUGGER_VERSION:
+            raise Exception("Incorrect debugger version from target: %d expected: %d" %
+                            (self.version, JERRY_DEBUGGER_VERSION))
+
 
         if self.little_endian:
             self.byte_order = "<"