SIGNAL no longer sends SMS...after a random time

Just to let you know:
Updated /e/ OS on my Nexus 5 yesterday, Signal app still working normally:-)

With the QR Code the installation did not work for me.

langis1 langis2 langis3

This is how it works: signal-gcm-less

To get the latest APK via direct download, click here.

But is this really “clean”?

langis4 langis5 langis6

I have been using Signal without any problem for more than 2 monts now.
Now if I open Signal a banner informs me that I have 9 days left to upgrade to a new version.
I can click on the banner and only APKPure and F-Droid are available for updating the app.
But I installed from the /e/ playstore. And the /e/ playstore is giving me no possibility to upgrade.
I find it a bit confusing. Are all installations, /e/, APKPure and F_Droid identical?
What should I do?

Regards,
André