So with Apple pushing out iOS firmwares like they candy we want users to know the best way to see what firmwares are being signed by Apple so they know what they can and can’t restore to. 

Right now the best way is to visit the site ipsw downloads. Their site tells you what firmwares are being signed. This is a big help for right when a new firmware is pushed by Apple seeing we don’t know how long the signing window stays open for the previous firmware. So make sure to check before you restore!