1. Theme alias and Department alias.
   1. https://doc.livehelperchat.com/docs/department/department#how-to-disable-user-to-change-department
   2. https://doc.livehelperchat.com/docs/theme/theme/#how-to-avoid-visitors-finding-out-existing-themes
2. PHP 8.1 compatibility fixes

These alias features will allow hiding completely existing departments from visitors. They won't see all of them if you make departments argument required and put a string for arguments.

For update just follow standard update procedure For manual update it's update_260.sql