Nearly three weeks after releasing iOS 9.3.4, Apple has closed the signing window for iOS 9.3.3 and iOS 9.3.2, making it impossible to downgrade from the latest firmware version available to these older ones.
Jailbreak users are accustomed to this process which lets them temporarily downgrade from the latest software version available to the previous one. Apple typically leaves a two-week window between the time the latest software is released and the time the previous one stops being signed.
For most users, this doesn’t really have any impact on the usage of their devices. However, for jailbreak users, this means that they should be extra careful not to accidentally update their devices to iOS 9.3.4, as there is now no going back.
iOS 9.3.4 was released on August 4 as a security update to patch exploits used by the Pangu Team in the release of their latest jailbreak for iOS 9.3.3. At this time, beyond the usual round of fakes floating around, there is no way to jailbreak iOS 9.3.4. iOS hacker Luca Todesco recently showed off a jailbroken iPhone running iOS 9.3.4, but it is very unlikely this will be released to the public.
If there is any viable jailbreak from Pangu Team or other competent group of hackers, it’s safe to assume it won’t be released until the upcoming release of iOS 10 next month.