my phone said there was a firefox update so I updated now firefox says this version is not supported so now I have no firefox - bloody useless

My android phone is a Samsung Galaxy Ace GT-I8160L currently running Android 4.1.2 I was advised in update notifications that a new update for Firefox was available. So went ahead and downloaded update and when I tried to install message reads your device does not support this version. Now I cant use Firefox because I have no way of rolling back to the previous version which worked absolutely fine. I hate the way new versions come out and there are no warnings before you install that the device is not supported. So which version should I be using and how do I download it onto my android phone? I loved Firefox until now and now I'm very disappointed. Maurice French +64 21 306275