Ok, this topic can now be marked as closed.
If you are interested in what happened, and what I did to fix the 500 Server errors, here it is:
In the update-process I did not understand that I should only copy from htdocs to my root category of dolibarr installation. So it kept all the original files under /dolibarr/ and then installed a new version on /htdocs/. (Maybe dolibarr should make this a little clearer)
I manually uploaded all new files in the .zip for the newest version and made them overwrite the current ones in /dolibarr/.
Then I deleted all files from /htdocs/ and checked the install -> it actually worked without 500 errors now.
New backup of DB / sql_dump.
then I opened my sql dump in notepad++ and ran a search&replace for the prefix llx_ to erp_ (just for the fun of it, never understood the llx anyway.))
Then a /Delete_All from webserver and mysql
New install, with new DB on the mariaDB database - set up in cpanel.
phpmyadmin -> delete ALL tables in the newly installed database
Then I ran my sql_dump with erp_ prefixes - and voila’
All good now!
Now I feel lucky, hope it will work tomorrow when we will ship some pallets from our warehouse.
