Apple has, without much ceremony, killed off its seven weeks old iOS 8.2, leaving iOS 8.3 the only version of its iOS which the company will allow to be installed on owner’s iPads, iPhones and iPod devices.
The trigger that killed iOS 8.2 is called 'code signing (opens in new tab)'. As Apple explains, code signing your app assures users that it is from a known source and the app hasn’t been modified since it was last signed.
"Before your Mac app or iOS app can be used with store services, installed on an iOS device for development or testing, or submitted to the App Store, it must be signed with a certificate issued by Apple.“
This happens as you install an app. Every version of the iOS must 'log in' with Apple's servers first and verify its identity. Only then does it have permission to be installed.
If Apple refuses to sign off the software it aborts, and the Twitter bot @TSSstatus has detected iOS 8.2 signatures are no longer being signed off.
What this means is that you can't upgrade, or downgrade, to any version other than the iOS 8.3. If you have 8.1 – you can't get to 8.2, and in case you have issues with the iOS 8.3 (it is said that the iOS 8.3 has notable security glitches) – there's nowhere you can go.
You can, however, stay at whatever version you're currently using, but don’t expect to upgrade to anything other than 8.3.
You can also stay put for another month, until the iOS 8.4 gets released.