PHP 8

You have to update your code for PHP 8.

Deprecated: Required parameter $arr follows optional parameter $insert in jsm-show-post-meta/lib/com/util.php on line 1917
Deprecated: Required parameter $match_key follows optional parameter $insert in jsm-show-post-meta/lib/com/util.php on line 1917
Deprecated: Required parameter $mixed follows optional parameter $insert in wp-jsm-show-post-meta/lib/com/util.php on line 1917

private static function insert_in_array( $insert = 'after', array &$arr, $match_key, $mixed, $add_value = null, $ret_bool = false ) {
...