diff --git a/src/antibot/antibot_data.h b/src/antibot/antibot_data.h
index fff2369a4..811210502 100644
--- a/src/antibot/antibot_data.h
+++ b/src/antibot/antibot_data.h
@@ -6,7 +6,7 @@
 
 enum
 {
-	ANTIBOT_ABI_VERSION=2,
+	ANTIBOT_ABI_VERSION=3,
 
 	ANTIBOT_MSGFLAG_NONVITAL=1,
 	ANTIBOT_MSGFLAG_FLUSH=2,
diff --git a/src/antibot/antibot_interface.h b/src/antibot/antibot_interface.h
index 8b75432d1..0f9af519a 100644
--- a/src/antibot/antibot_interface.h
+++ b/src/antibot/antibot_interface.h
@@ -22,7 +22,7 @@ void AntibotOnDirectInput(int ClientID);
 void AntibotOnCharacterTick(int ClientID);
 void AntibotOnHookAttach(int ClientID, bool Player);
 void AntibotOnEngineTick(void);
-void AntibotOnEngineClientJoin(int ClientID);
+void AntibotOnEngineClientJoin(int ClientID, bool Sixup);
 void AntibotOnEngineClientDrop(int ClientID, const char *pReason);
 void AntibotOnEngineClientMessage(int ClientID, const void *pData, int Size, int Flags);
 
diff --git a/src/antibot/antibot_null.cpp b/src/antibot/antibot_null.cpp
index 1950b850d..aa8ffef2c 100644
--- a/src/antibot/antibot_null.cpp
+++ b/src/antibot/antibot_null.cpp
@@ -32,7 +32,7 @@ void AntibotOnDirectInput(int ClientID) { (void)ClientID; }
 void AntibotOnCharacterTick(int ClientID) { (void)ClientID; }
 void AntibotOnHookAttach(int ClientID, bool Player) { (void)ClientID; (void)Player; }
 void AntibotOnEngineTick(void) { }
-void AntibotOnEngineClientJoin(int ClientID) { (void)ClientID; }
+void AntibotOnEngineClientJoin(int ClientID, bool Sixup) { (void)ClientID; (void)Sixup; }
 void AntibotOnEngineClientDrop(int ClientID, const char *pReason) { (void)ClientID; (void)pReason; }
 void AntibotOnEngineClientMessage(int ClientID, const void *pData, int Size, int Flags) { (void)ClientID; (void)pData; (void)Size; (void)Flags; }
 
diff --git a/src/engine/antibot.h b/src/engine/antibot.h
index f8a3637cc..d5d48d116 100644
--- a/src/engine/antibot.h
+++ b/src/engine/antibot.h
@@ -35,7 +35,7 @@ public:
 
 	// Hooks
 	virtual void OnEngineTick() = 0;
-	virtual void OnEngineClientJoin(int ClientID) = 0;
+	virtual void OnEngineClientJoin(int ClientID, bool Sixup) = 0;
 	virtual void OnEngineClientDrop(int ClientID, const char *pReason) = 0;
 	virtual void OnEngineClientMessage(int ClientID, const void *pData, int Size, int Flags) = 0;
 
diff --git a/src/engine/server/antibot.cpp b/src/engine/server/antibot.cpp
index 4401f7e1d..96e972f26 100644
--- a/src/engine/server/antibot.cpp
+++ b/src/engine/server/antibot.cpp
@@ -106,7 +106,7 @@ void CAntibot::OnCharacterTick(int ClientID) { Update(); AntibotOnCharacterTick(
 void CAntibot::OnHookAttach(int ClientID, bool Player) { Update(); AntibotOnHookAttach(ClientID, Player); }
 
 void CAntibot::OnEngineTick() { Update(); AntibotOnEngineTick(); }
-void CAntibot::OnEngineClientJoin(int ClientID) { Update(); AntibotOnEngineClientJoin(ClientID); }
+void CAntibot::OnEngineClientJoin(int ClientID, bool Sixup) { Update(); AntibotOnEngineClientJoin(ClientID, Sixup); }
 void CAntibot::OnEngineClientDrop(int ClientID, const char *pReason) { Update(); AntibotOnEngineClientDrop(ClientID, pReason); }
 void CAntibot::OnEngineClientMessage(int ClientID, const void *pData, int Size, int Flags)
 {
@@ -159,7 +159,7 @@ void CAntibot::OnCharacterTick(int ClientID) { }
 void CAntibot::OnHookAttach(int ClientID, bool Player) { }
 
 void CAntibot::OnEngineTick() { }
-void CAntibot::OnEngineClientJoin(int ClientID) { }
+void CAntibot::OnEngineClientJoin(int ClientID, bool Sixup) { }
 void CAntibot::OnEngineClientDrop(int ClientID, const char *pReason) { }
 void CAntibot::OnEngineClientMessage(int ClientID, const void *pData, int Size, int Flags) { }
 #endif
diff --git a/src/engine/server/antibot.h b/src/engine/server/antibot.h
index 8639f5d03..6b10df979 100644
--- a/src/engine/server/antibot.h
+++ b/src/engine/server/antibot.h
@@ -30,7 +30,7 @@ public:
 	virtual void Init();
 
 	virtual void OnEngineTick();
-	virtual void OnEngineClientJoin(int ClientID);
+	virtual void OnEngineClientJoin(int ClientID, bool Sixup);
 	virtual void OnEngineClientDrop(int ClientID, const char *pReason);
 	virtual void OnEngineClientMessage(int ClientID, const void *pData, int Size, int Flags);
 
diff --git a/src/engine/server/server.cpp b/src/engine/server/server.cpp
index ea222886a..439f6d03d 100644
--- a/src/engine/server/server.cpp
+++ b/src/engine/server/server.cpp
@@ -991,7 +991,7 @@ int CServer::NewClientCallback(int ClientID, void *pUser, bool Sixup)
 	pThis->m_aClients[ClientID].Reset();
 
 	pThis->GameServer()->OnClientEngineJoin(ClientID, Sixup);
-	pThis->Antibot()->OnEngineClientJoin(ClientID);
+	pThis->Antibot()->OnEngineClientJoin(ClientID, Sixup);
 
 	pThis->m_aClients[ClientID].m_Sixup = Sixup;