move website to a new server and need to update PHP version to 8.3

Hi -  (not sure if the Forum ID I chose is correct) When my webhosting service, who is updating things, does that (update PHP version to 8.3), the website fails.  website: www.standardcartage.com The error message that shows is the following: [09-Nov-2025 17:34:15 UTC] PHP Fatal error:  Declaration of catchthemes_search_form::widget($args) must be compatible with WP_Widget::widget($args, $instance) in /home/standard/public_html/wp-content/themes/catch-mustang/functions/catchthemes_widgets.php on line 1289 He says:  the theme catch mustang needs an update to be able to work with PHP 8.3. I can't see how to update catch mustang. Does my license need to be active? Thank you