Hm. Thanks for moving this to its own topic … I guess.
Updating the underlying raspbian OS of EmonPi truely comes with its issues but it’s not impossible. Although I wonder why it’s so tightly entangled with the debian configuration. But perhaps that’s an php issue and how packages are being updated in Debian. In the current setup describing the setup as hazardous is true. At least now I know how these services interact. A non-programmer probably would have given up pretty soon. I was curious and did not want to setup everything again. Investing an hour in getting it to run again deemed perfectly fair
What I previously forgot which may be also a problem in the OpenSuse case is that Apache stopped loading the redis extension for some reason.
In Raspbian this was the case because of the update. It disabled the redis extension for the old Apache PHP 7.0 configuration. It was perfectly working with the newly installed PHP 7.3. But Apache for EmonCMS was configured to use PHP 7.0 for which the redis extension got disabled. Simply enabling did not fix it. But updating redis library with pecl brought it back to life.
During the Raspbian Update following happend:
/etc/php/7.0/mods-available/redis.ini got moved to /etc/php/7.0/mods-available/redis.ini.dpkg-bak.
Which makes perfectly sense when the new redis extension is no longer compatible for whatever reason.
Updating redis libarary and putting the file back in place fixed it.
So in addition to what I wrote on the top following needs to be done:
sudo apt purge php-redis
sudo pecl install redis
mv /etc/php/7.0/mods-available/redis.ini.dpkg-bak /etc/php/7.0/mods-available/redis.ini
sudo systemctl restart apache