Stop this version from loading on newer blenders

__init__.py

@@ -1,7 +1,24 @@
+import bpy
+from bpy.app.handlers import persistent
+
 modules = None
 ordered_classes = None
 
+def show_version_error_popup():
+    def draw(self, context):
+        self.layout.label(text="Sorry, this version of Avatar Toolkit does not work on this version of Blender.")
+        self.layout.label(text="Please check the GitHub repository for the correct version for your Blender.")
+        self.layout.operator("wm.url_open", text="Open GitHub Repository").url = "https://github.com/teamneoneko/Avatar-Toolkit"
+    
+    bpy.context.window_manager.popup_menu(draw, title="Avatar Toolkit Version Error", icon='ERROR')
+
 def register():
+    # Check Blender version first
+    version = bpy.app.version
+    if version[0] > 4 or (version[0] == 4 and version[1] > 3):
+        show_version_error_popup()
+        return
+    
     # Add wheel installation check
     try:
         import lz4