new Joomla installation, everything updated, Error reporting in global configuration set to Maximum.
When I go to any plugin settings and save it, Joomla 500 error is displayed, settings is not saved.
At the top of page and in PHP error log is
PHP Deprecated: trim(): Passing null to parameter #1 ($string) of type string is deprecated in /..../plugins/system/admintools/src/Feature/ProtectAgainstDeactivation.php on line 149
Probably PHP 8.1 issue. Could be solved by switching off Error reporting in global configuration.