Last v3.0 not compatible with PHP 7.2 and 7.3

Than you for the last update. This version v3.0 is unfortunately not compatible with PHP 7.2 and 7.3 due to specific PHP 7.4 syntax in the code.

For example in wp-content/plugins/responsive-videos-fitvids/lib/Core/Bootstrap.php on line 24:
private static ?Bootstrap $instance = null;
Results in error:
PHP Parse error: syntax error, unexpected ‘?’, expecting function (T_FUNCTION) or const (T_CONST)

Or in line 30:
private static function Bootstrap $instance = null;
Results in error:
PHP Parse error: syntax error, unexpected ‘array’ (T_ARRAY), expecting function (T_FUNCTION) or const (T_CONST)