diff --git a/modules/client_locales/locales.lua b/modules/client_locales/locales.lua
index 71a9873c..52e4c1e7 100644
--- a/modules/client_locales/locales.lua
+++ b/modules/client_locales/locales.lua
@@ -13,7 +13,7 @@ local localeComboBox
 local function sendLocale(localeName)
   local protocolGame = g_game.getProtocolGame()
   if protocolGame then
-    protocolGame:sendExtendedOpcode(0, localeName)
+    protocolGame:sendExtendedOpcode(1, localeName)
     return true
   end
   return false
@@ -63,7 +63,7 @@ function Locales.init()
               localeComboBox.onOptionChange = onLocaleComboBoxOptionChange
             end, false)
 
-  Extended.register(0, onServerSetLocale)
+  Extended.register(1, onServerSetLocale)
   connect(g_game, { onGameStart = onGameStart })
 end
 
@@ -71,7 +71,7 @@ function Locales.terminate()
   installedLocales = nil
   currentLocale = nil
   localeComboBox = nil
-  Extended.unregister(0)
+  Extended.unregister(1)
   disconnect(g_game, { onGameStart = onGameStart })
 end
 
diff --git a/src/otclient/CMakeLists.txt b/src/otclient/CMakeLists.txt
index a1a5a40c..1a83cd55 100644
--- a/src/otclient/CMakeLists.txt
+++ b/src/otclient/CMakeLists.txt
@@ -5,7 +5,6 @@ ENDIF(${CMAKE_MAJOR_VERSION} EQUAL 2 AND ${CMAKE_MINOR_VERSION} EQUAL 6)
 
 # otclient options
 OPTION(BOT_PROTECTION "Enable bot protection" ON)
-OPTION(EXTENDED_OPCODE "Enable extended opcode" OFF)
 SET(PROTOCOL 860 CACHE "Protocol version" STRING)
 OPTION(CIPSOFT_RSA "Use cipsoft RSA to login into original tibia" OFF)
 ADD_DEFINITIONS(-DPROTOCOL=${PROTOCOL})
@@ -25,13 +24,6 @@ ELSE(BOT_PROTECTION)
     MESSAGE(STATUS "Bot protection: OFF")
 ENDIF(BOT_PROTECTION)
 
-IF(EXTENDED_OPCODE)
-    ADD_DEFINITIONS(-DEXTENDED_OPCODE)
-    MESSAGE(STATUS "Extended opcode: ON")
-ELSE(EXTENDED_OPCODE)
-    MESSAGE(STATUS "Extended opcode: OFF")
-ENDIF(EXTENDED_OPCODE)
-
 SET(otclient_SOURCES ${otclient_SOURCES}
     # otclient
     ${CMAKE_CURRENT_LIST_DIR}/otclient.cpp
diff --git a/src/otclient/net/protocolcodes.h b/src/otclient/net/protocolcodes.h
index dad57f19..b63c0b31 100644
--- a/src/otclient/net/protocolcodes.h
+++ b/src/otclient/net/protocolcodes.h
@@ -105,7 +105,7 @@ namespace Proto {
         GameServerChallange                 = 31,
         GameServerDeath                     = 40,
 
-        // all in game opcodes must be equal or greater than 50
+        // all in game opcodes must be greater than 50
         GameServerFirstGameOpcode           = 50,
 
         // otclient ONLY
diff --git a/src/otclient/net/protocolgame.h b/src/otclient/net/protocolgame.h
index cfd3d1f7..9ba96e1f 100644
--- a/src/otclient/net/protocolgame.h
+++ b/src/otclient/net/protocolgame.h
@@ -213,6 +213,7 @@ public:
     Position getPosition(const InputMessagePtr& msg);
 
 private:
+    Boolean<false> m_enableSendExtendedOpcode;
     Boolean<false> m_gameInitialized;
     std::string m_accountName;
     std::string m_accountPassword;
diff --git a/src/otclient/net/protocolgameparse.cpp b/src/otclient/net/protocolgameparse.cpp
index dad75c61..280ac6d9 100644
--- a/src/otclient/net/protocolgameparse.cpp
+++ b/src/otclient/net/protocolgameparse.cpp
@@ -46,7 +46,7 @@ void ProtocolGame::parseMessage(const InputMessagePtr& msg)
             if(callLuaField<bool>("onOpcode", opcode, msg))
                 continue;
 
-            if(!m_gameInitialized && opcode >= Proto::GameServerFirstGameOpcode)
+            if(!m_gameInitialized && opcode > Proto::GameServerFirstGameOpcode)
                 logWarning("received a game opcode from the server, but the game is not initialized yet, this is a server side bug");
 
             switch(opcode) {
@@ -1212,13 +1212,16 @@ void ProtocolGame::parseExtendedOpcode(const InputMessagePtr& msg)
     int opcode = msg->getU8();
     std::string buffer = msg->getString();
 
-#ifdef EXTENDED_OPCODE
-    try {
-        callLuaField("onExtendedOpcode", opcode, buffer);
-    } catch(Exception& e) {
-        logError("Network exception in extended opcode ", opcode, ": ", e.what());
+    if(opcode == 0) {
+        m_enableSendExtendedOpcode = true;
+    }
+    else {
+        try {
+            callLuaField("onExtendedOpcode", opcode, buffer);
+        } catch(Exception& e) {
+            logError("Network exception in extended opcode ", opcode, ": ", e.what());
+        }
     }
-#endif
 }
 
 void ProtocolGame::setMapDescription(const InputMessagePtr& msg, int x, int y, int z, int width, int height)
diff --git a/src/otclient/net/protocolgamesend.cpp b/src/otclient/net/protocolgamesend.cpp
index 6dd512b2..690fd3d5 100644
--- a/src/otclient/net/protocolgamesend.cpp
+++ b/src/otclient/net/protocolgamesend.cpp
@@ -33,13 +33,13 @@ void ProtocolGame::safeSend(const OutputMessagePtr& outputMessage)
 
 void ProtocolGame::sendExtendedOpcode(uint8 opcode, const std::string& buffer)
 {
-#ifdef EXTENDED_OPCODE
-    OutputMessagePtr msg(new OutputMessage);
-    msg->addU8(Proto::ClientExtendedOpcode);
-    msg->addU8(opcode);
-    msg->addString(buffer);
-    safeSend(msg);
-#endif
+    if(m_enableSendExtendedOpcode) {
+        OutputMessagePtr msg(new OutputMessage);
+        msg->addU8(Proto::ClientExtendedOpcode);
+        msg->addU8(opcode);
+        msg->addString(buffer);
+        safeSend(msg);
+    }
 }
 
 void ProtocolGame::sendLoginPacket(uint challangeTimestamp, uint8 challangeRandom)