Is Unity Android free for all editions?

Is Android completely free now for every Unity edition, or just for Unity 4.2?

I'm asking because I just upgraded to Unity 4.2 and I was using a free key before for Android that they gave away during their big give away a few years ago. I think I might have lost the key for it now though. I also need to downgrade to 4.1.5 because 4.2 is too unstable.