F-Droid Basic was automatically updated to F-Droid Basic 2.0 RC. Before the update, all F-Droid apps were updated automatically. That is no longer the case. I have to manually initiate all the updates. Although I receive a notification that an update is available, the update is never installed automatically—not even if I wait several days.
The Autoupdate setting has explainer text, read it.
That’s exact my problem. Currently it’s set to:
Download and update apps daily even on mobile data when the device isn’t being used.
Since most of the time, the device wait on the desktop, this should be the case really often. But also after waiting 3 days, the update is not installed. Only announced.
you didn’t name your device, your Android version
you didn’t email team at f-droid.org your saved debug log explaining that your device NEVER sleeps
etc
I don’t understand. What should I do? When you say I should send a mail to someone, what is the mail address and what should I insert into the mail? I have not give my device a name as of yet. Is that important? Where can I do that? How do I get a debug log?
We are lost in translation? 
Which device model? Which Android version?
Go to F-Droid client, Settings, Debug, save the log when asked, email that to: team AT f-droid.org (read this outloud, you might be surprised)