Apple Stopped signing iOS 9.2.1 from today. That means you can’t downgrade anymore. The downgrade portal is off forever from today for iOS 9.2.1.
As for those of folks who are on iOS 9.2.1, I strongly recommend you stay on that firmware and wait patiently for the next jailbreak release. If the recent release of Pangu iOS 9.1 jailbreaks has taught us anything, it is to stay on as low firmware version as possible and wait for the next jailbreak. Well, I know it hurts but if you are not on iOS 9.1 and you love jailbreak then you have to make that tough choice.
And If you are on iOS 9.3 though, I will recommend updating to iOS 9.3.1. This is because from the security perspective, iOS 9.3 and iOS 9.3.1 are essentially the same firmware. If there is a future jailbreak release for iOS 9.3, it will likely work on iOS 9.3.1 as well, therefore, we highly recommend updating to iOS 9.3.1 from iOS 9.3 as it includes the important fix for broken universal links issue. And its always better to stay up to date with the latest iOS version for the general people.
Jailbreak users, they don’t fall under general people as they are more advanced and not a newbie. So guys stay there in iOS 9.2.1. Jailbreak developers are working the release.