PHP error on PHP 8.0

Hello!

I tried to switch from PHP 7.4 to PHP 8.0 but I got a WP critical error page and the following to my email:

Tiedoston /PATH/TO/MY/WP/INSTALLATION/wp-content/plugins/wp-smushit/lib/class-wp-smush.php rivill? 1206 havaittiin virhe lajia E_ERROR. Virheviesti: Uncaught ValueError: version_compare(): Argument #3 ($operator) must be a valid comparison operator in /PATH/TO/MY/WP/INSTALLATION/wp-content/plugins/wp-smushit/lib/class-wp-smush.php:1206
Stack trace:
#0 /PATH/TO/MY/WP/INSTALLATION/wp-content/plugins/wp-smushit/lib/class-wp-smush.php(1206): version_compare()
#1 /PATH/TO/MY/WP/INSTALLATION/wp-content/plugins/wp-smushit/lib/class-wp-smush.php(172): WpSmush->migrate()
#2 /PATH/TO/MY/WP/INSTALLATION/wp-includes/class-wp-hook.php(307): WpSmush->admin_init()
#3 /PATH/TO/MY/WP/INSTALLATION/wp-includes/class-wp-hook.php(331): WP_Hook->apply_filters()
#4 /PATH/TO/MY/WP/INSTALLATION/wp-includes/plugin.php(476): WP_Hook->do_action()
#5 /PATH/TO/MY/WP/INSTALLATION/wp-admin/admin.php(175): do_action()
#6 /PATH/TO/MY/WP/INSTALLATION/wp-admin/options-general.php(10): require_once('...')
#7 {main}
  thrown

Kindly,
Juuso