How to downgrade my iphone 4s to an iOS before 8.1?

I'm trying to get GBA4iOS and it will only work for an iOS thats before 8.1, any ideas?

You can't, Apple have stopped signing any firmware bellow IOS 8, until someone finds out how to bypass the verification, there's no way of downgrading.

You can't but I personally avoid downloading updates until I hear reviews about so in the future if you wait two days you can find out all the issues and decide if it's worth it