Those who brought Xiaomi 14 or other Xiaomi phones from china with Chinese ROM Miui or Hyperos and have problems with delay or not receiving notifications on WhatsApp or other app this will help you to fix your issues... First of all turn on all notifications settings from app settings and mobile notification settings then Go to phone main settings go to my device click on the OS version several time when you see (you are now developer) now go back to setting scroll down there find Additional settings Now scroll down and see for Developer Options in this go straight down find (Turn on system optimization) turn it off wait for 2 to 3 minutes restart Mobile and turn system optimization on again.. after you see you receive notifications... enjoy...