With iOS 8.4 due out in just under 3 hours now is the time to make sure your prepared. 

If you are Jailbroken on a lower firmware now would be the time to upgrade to 8.3 as there are well over 300 tweaks now compatible and by being on 8.3 you do not have to jailbreak straight away you can wait until it is confirmed whether or not apple have patched the jailbreak in 8.4. 

iOS 8.3 fixes several bugs found in older firmware and so by being on 8.3 you have the peace of mind that you are less likely to have a buggy version of iOS if another jailbreak is not released for some time.