Deprecated usage of constant FILTER_SANITIZE_STRING

Using Imagify Version ?2.1.1 with PHP 8.1 results in the following deprecation message:
Deprecated: Constant FILTER_SANITIZE_STRING is deprecated in /my-abs-path-to-wordpress/wp-content/plugins/imagify/inc/classes/class-imagify-views.php on line?511

See https://www.php.net/manual/en/filter.constants.php where it is explained, that one should use htmlspecialchars() instead of

filter_input( INPUT_GET, 'page', FILTER_SANITIZE_STRING );