Error Message on Update to PHP 8.5

I'm receiving the following error when i attempt to update to PHP 8.5 | any help would be greatly appreciated.

Fatal error: Cannot redeclare function array_first() in /home/creditsc/public_html/cmsAdmin/lib/array_functions.php on line 6 Stack trace: #0 /home/creditsc/public_html/cmsAdmin/lib/init.php(26): Itools\Cmsb\init() #1 /home/creditsc/public_html/cmsAdmin/lib/viewer_functions.php(13): require_once('/home/creditsc/...') #2 /home/creditsc/public_html/collections/workAccounts.php(8): include_once('/home/creditsc/...') #3 {main}