If you would like to find out what has changed since BioStar 2.6 and above, with regards to Custom Level, please refer to the article
How to Configure a Custom Level
In BioStar 2.5 or below, all users who have the privilege of Monitoring can see all event logs which are generated in the Monitoring section. From Biostar 2.6, you can configure the accessible custom items such as User, Device, Door, Elevator and Zone to limit the items that can be monitored.
1. Go to the Settings > ACCOUNT.
2. Create new Custom Level. At this point, you can configure the Monitoring’s custom items.