MB Custom Post Type causes PHP Fatal error after upgrading to PHP 8.0

Hi Peter,

Thanks for your reply.

Yes, I tried to deactivate all plugins except the Meta Box base and MB Custom Post Type plugins. This issue persists.

As the error.log shows (I pasted the snippet below):

PHP message: PHP Fatal error: Uncaught TypeError: strpos(): Argument #1 ($haystack) must be of type string, array given in /www/site/public/wp-includes/media.php:3721
Stack trace:
#0 /www/site/public/wp-includes/media.php(3721): strpos(Array, 'attachment:')
#1 /www/site/public/wp-admin/menu.php(71): get_taxonomies_for_attachments('objects')
#2 /www/site/public/wp-admin/admin.php(158): require('/www/site...')
#3 /www/site/public/wp-admin/index.php(10): require_once('/www/site...')
#4 {main}
thrown in /www/site/public/wp-includes/media.php on line 3721" while reading response header from upstream

The first argument of the strpos function receives an array which may be unacceptable in PHP 8.0. So tried to add the code before the strpos function in the media.php file. Then the warning message does not show again.

if( gettype( $object_type ) == 'array' ){
    $object_type = implode( "", $object_type );
}