diff --git a/game/shared/igamesystem.h b/game/shared/igamesystem.h
index 369c4261..9e22bae7 100644
--- a/game/shared/igamesystem.h
+++ b/game/shared/igamesystem.h
@@ -286,6 +286,7 @@ public:
 	virtual void unk_302( const void *const msg ) = 0;
 	virtual void unk_303( const void *const msg ) = 0;
 	virtual void unk_304( const void *const msg ) = 0;
+	virtual void unk_305( const void *const msg ) = 0;
 
 	GS_EVENT_IMPL( GameFrameBoundary );
 	GS_EVENT_IMPL( OutOfGameFrameBoundary );
@@ -386,6 +387,7 @@ public:
 	virtual void unk_302( const void *const msg ) override {}
 	virtual void unk_303( const void *const msg ) override {}
 	virtual void unk_304( const void *const msg ) override {}
+	virtual void unk_305( const void *const msg ) override {}
 
 	GS_EVENT( GameFrameBoundary ) {}
 	GS_EVENT( OutOfGameFrameBoundary ) {}