Apple released today iOS 9.2.1 to the public, a release that is available as an over-the-air update to all iOS 9 users.
iOS 9.2.1 is a minor incremental update, focusing on performance improvements and bug fixes including a fix for a significant Mobile Device Management issue that affected enterprise customers.
This update contains security updates and bug fixes including a fix for an issue that could prevent the completion of app installation when using an MDM server.