Don’t have to:

“When the app is first started on an Android device, it starts the background [“in Android terminology, a "foreground service" showing a notification icon when the service is running”] service that keeps the TCP connections to the messaging servers open with almost no traffic (only doing periodic checks that connections still exist). It consumes only a few percents of battery per day, depending on how stable your internet connection is, and delivers message notifications as soon as messages arrive.

This service continues running when the app is switched off, and it is restarted when the device is restarted even if you don't open the app - so the message notifications arrive instantly every time. To maximize battery life, it can be turned off by switching off "Private notifications". You will still receive notifications while the app is running or in the background.

So, for Android we can now deliver instant message notifications without compromising users' privacy in any way.”

https://simplex.chat/blog/20220404-simplex-chat-instant-notifications.html