Hi Mathieu,
Thanks for the advice!
I did that and got a bunch of “deprecated” messages plus this one:
Notice: register_uninstall_hook was called incorrectly. Only a static class method or function can be used in an uninstall hook. Please see Debugging in WordPress for more information. (This message was added in version 3.1.) in /homepages/31/d447767621/htdocs/wordpress/wp-includes/functions.php on line 3622
Now, I am not sure what to do with this as the quoted line 3622 in the functions.php is just the function for displaying the error message.
There was one plugin which showed up with faulty code when I ran a simple Google Chrome “Inspect Element”. I have uninstalled it. But the error persists…
So I installed a debugger plugin (Debug This) to get more intel on which plugin has the wrong uninstall hook. Unfortunately, I had to realize that the WP admin bar does not display on the home or the archive pages. And without admin bar I can’t run Debug This on the faulty pages…
What do you think? Is deinstalling every single plugin the way to go?
Thanks!
Carola