Hi there,
This dropped recently – yesterday. Not sure what it contains but I know it is very small indeed. The readme / release notes were brief too. I did get unknown errors downloading the update. Likely due to how busy it is? While I had issues yesterday with updating all my devices, this morning I had no issues.
=== release notes start
iOS 9.2.1
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.
For information on the security content of this update, please visit this website:
https://support.apple.com/en-us/HT205732
=== release notes end
Actually, when I clicked on that URL there was nothing specific for iOS 9.2.1 – update – it does now. You can see a little more in this article or this one.
I can say I have updated an iPhone 6s, and an iPad Air 2 with no issues – other then the network ones I mention above. So far, I have not noticed anything new or different.
Update:
- 1/22/16 – Why this update matters – see this.
Michael
=== END ===