What operating systems are supported?
NiDB has been designed for CentOS and has been tested on CentOS7, CentOS8. RHEL is supposed to be compatible with CentOS, so in theory there should be no issues installing NiDB on RHEL7 or 8. However, there may be some configuration differences between the installations.
Ubuntu, and other distributions have not been extensively tested nor has an installer created, but as long as MariaDB 10+, PHP7+, Qt5.12.8 are available, and the nidb binary has been compiled for that OS, then there should be no problems running the NiDB database.
How do I enable/disable GUI options displayed to users?
Under the Admin → Settings… menu, there are several options available to control if DICOM data can be downloaded, if the calendar is available, if recently collected studies are displayed, if remote connections should be available, etc.