Add a warning for outdated installations

modules/one_click_installer_check.py

@@ -0,0 +1,8 @@
+from pathlib import Path
+from modules.logging_colors import logger
+
+if Path('../webui.py').exists():
+    logger.warning('\nIt looks like you are running an outdated version of '
+                   'the one-click-installers.\n'
+                   'Please migrate your installation following the instructions here:\n'
+                   'https://')

server.py

@@ -1,6 +1,7 @@
 import os
 import warnings
 
+import modules.one_click_installer_check
 from modules.block_requests import OpenMonkeyPatch, RequestBlocker
 from modules.logging_colors import logger