On June 7th, 201 Apple announced the upcoming release of iOS 15. At this time this software is in "BETA" (testing phase) - this status indicates the OS is not ready for public release or support.
IS&T does not support iOS 15 while in BETA. This article will be periodically updated as Apple announced a release date / supported devices.
Please note that IS&T does support iOS 13 and iOS 14 for things like calendars, email, contacts.
For information about iPadOS 14, please see KB article iPadOS 14 at MIT.