Warning: Undefined variable

Since update to PHP 8.1 start getting this warning.
Warning: Undefined variable $parentDashboardDefaultTabCount in /home/xxxxxx/public_html/eschool/src/UI/Dashboard/ParentDashboard.php on line 833
Gibbon version 26, PHP 8.1.
There was no problem with PHP 7.4.
Any idea, help how to fix this…please.
Thanks

Yes, this is possible with the newer versions of PHP, as they are introducting more strict type checking. In this case, it is just a PHP warning, not an error, and these types of messages are really only used for development purposes. We do always try to fix any warnings we come across, but they will not impact your use of Gibbon. In production, be sure to set your error message so they don’t show warnings, notifications or deprecations, which are just for developers. This usually means setting your error reporting level to something like E_ERROR in your php.ini file, or adding something like ini_set('error_reporting', E_ERROR); to the bottom of your config.php file.