Notifications and background activity

[Taifun]

I do not know, I'm not familiar with that extension... itoo is the most powerful extension concerning background functionality...

just experiment yourself and let us know what you find out...

See also @SteveJG 's comment and example here

Background processing

You also can use the UrsAI2KeepAlive zip archive Ullis Roboter Seite/AI2 Keep Alive The archive contains the source code, the compiled binary for uploading to the App Inventor and a discussion of how Ullis' Foreground extensions work. Several examples that show how this was done with gps are examples of the technique: Foreground GPS Location Service experiments and Tutorial by SteveJG that could be adapted to your purposes to post your messages.

Taifun