Don't Install If You're Jailbroken
Don't install the iOS 9.3.5 update if you jailbreak your iPhone or iPad. Why? Simple. You'll lose your jailbreak.
The iOS 9.3.4 update closed up the iOS 9.3.3 jailbreak. If you accidentally make the move to iOS 9.3.5 you can drop back down to the iOS 9.3.4 update but you can't drop down to iOS 9.3.3 to use the jailbreak.
If you're jailbroken or are thinking about jailbreaking you'll need to avoid the iOS 9.3.5 update until a working jailbreak is released.
We could see jailbreak developers release a jailbreak for it down the road though nothing is guaranteed at this point.
For more on the iOS 9.3.3 jailbreak, head here.