In my previous article, I have introduced how to downgrade your iPhone 5S from iOS 8.1.1 to iOS 8.1. But now, if you still want to downgrade from iOS 8.1.1 to iOS 8.1, you need to take it easy, for Apple has closed iOS 8.1 signing window, eliminating chance to downgrade.
According to 9to5 Mac, Apple has closed the signing window for iOS 8.1 on compatible iPhone, iPad and iPod touch models, thereby eliminating the ability for users to downgrade to the software version. iOS 8.1.1, seeded as an over the air update a few weeks ago, is now the earliest software version that devices can be restored to.
If you are currently using an iPhone, iPad or iPod touch that is running iOS 8.1, you should remember that there is no chance for you to go back to that software version if you upgrade at this point. The good news for jailbroken users is that an iOS 8.1.1 untethered jailbreak has already been released for Windows, with an OS X tool on the horizon.