If you are upgrading from a version prior to 2.6.0, make sure to go through all the release notes available here.
#3793: Porblem when creating an empty hostgroup with non admin user
#3795: Update Centreon Administration About page (forge -> Github)
#3796: Problem when connect two time with same user in API
#3797: Password in macro
#3800: Current State Duration isn’t displayed
#3803: ACL : Manage multiple Resources group on the same ACL user group
#3807: Unable to enable status option on main.cfg