After update osmc from 2020.11-1 to 2021.08-1 statement from config.txt missing

I’m not a native speaker, so if is problem unclear please ask.

Hardware: RPi 3+ B plus HiFiBerry AMP+ (not AMP2) as HAT to RPi.
Software: osmc since Aug 2016 with osmc default skin.

Since the update to latest osmc with MyOSMC Manual Update did not work, the error message was only displayed for a moment and it said something about connection problem, I used SSH from Ubuntu 21.04 Desktop to osmc and initiated the update from the comandline: sudo systemctl start manual-update.

After the update finished and RPi rebooted there was no sound. I found out that the line dtoverlay=hifiberry-amp was neither in /boot/config.txt nor in /boot/config-user.txt.

I suspect the old HiFiBerry amplifier AMP+ is a seldom used piece of hardware and tests during development didn’t show this problem.

This is expected and is covered in the release notes.
Editing /boot/config.txt manually or via My OSMC is now deprecated and changes you make can be replaced by the My OSMC update system.


I didn’t read the release notes and I can’t find them on The split of config.txt into 2 files and the Warning at the beginning of the new config.txt file gave a clear message, but I expected the upgrade would move ‘unusual entries’ to config-user.txt. Where can I find the release notes, please send a link.
Regards from Vienna, Austria,