Getting it running again (after my web-space provider’s PHP changes) was only a matter of re-running the configuration script:
http://[domain]/[directory]/mw-config/index.php
It asks for the UpgradeKey from here:
http://[domain]/[directory]/LocalSettings.php
After that I installed the latest MediaWiki tar ball.
I took a few notes in my diary, labeled MediaWiki.
At last I changed a few articles and I created a new one:
Well, I missed my gym class, but now I am going for a 10 km on the treadmill.