Running the latest and greatest beta software can be exciting. It can also be premature, as there's a reason why they call it beta testing. For those with a device running iOS 12 beta, downgrading back to iOS 11 may be a preferred option. This means re-joining the wait for a public release of iOS 12 this fall.
Apple has stopped signing iOS version 10.3.1 right on schedule. Now that approximately one month has passed since the release of iOS 10.3.2, device owners will not be able to install or downgrade to the previous version. The news comes after Apple seeded the fourth iOS 10.3.3 beta to developers last week.
iPhone owners looking to downgrade from iOS 10 to the previous version (iOS 9.3.5) are out of luck. This week, Apple stopped signing the latest iOS 9 firmware. This means that downgrading to the earlier operating system is not possible. At this time, the only versions of iOS that can be installed are iOS 10.0.2 and 10.0.3. Apple released iOS 10.0.3 exclusively for the iPhone 7 and iPhone 7 Plus. For all other iPhones iOS 10.0.2 remains the current version.
Beta testing is always a risky business, especially if you are installing the unproven software on your main device. The whole point of beta testing is to identify bugs and instabilities in software that has not yet been officially released. As such, there is always the possibility of installing the software and finding that your device constantly crashes in certain situations, or certain features no longer work. For instance, the 9.3 beta has elicited complaints about Bluetooth not working properly.
The famous downgrade tool TinyUmbrella was recently updated to a new beta version, despite the fact that downgrading iOS 8.x is not yet possible. Saving firmware SHSH blobs is always a safe bet, as one never knows when they might be needed should a downgrade solution be released.
For the time being, jailbreakers are warned to avoid updating iOS. Moving to iOS 8.2 will result in the loss of any installed jailbreak. While TinyUmbrella developer semaphore sees downgrade possibilities on the horizon, at the present time backing up SHSH blobs locally is just insurance. Until a downgrade is released, here are instructions on how to save iOS SHSH blobs with TinyUmbrella: