So I dutifully upgraded my version and everything is working OK except:
1. my /wp-admin/plugins.php isn't accessible anymore
2. my /wp-admin/themes.php isn't accessible either
3. my /wp-admin/theme-editor.php doesn't play nice either
Everything else appears to be working OK... Checked whether the files were there and they are. and surprisingly, places like wp-admin/plugin-editor.php seem to work...
Bit of a head scratcher that one... Any ideas?