FYI, Possible PHP Compatibility Issue

Using “PHP Compatibility Checker“, two possible errors are shown:
PHP 8.0 incompatibilities: FILE: event-organiser-debug.php FOUND 2 ERRORS AND 0 WARNINGS AFFECTING 2 LINES

158 | ERROR | Extension 'mysql_' is deprecated since PHP 5.5 and removed since PHP 7.0; Use mysqli instead
557 | ERROR | Extension 'mysql_' is deprecated since PHP 5.5 and removed since PHP 7.0; Use mysqli instead

I’m not aware that this affects the main plugin.