Board Thread:Plants vs. Zombies 2/@comment-26127523-20170410095839

I'm currently on ios7.0.4. I've resisted updating to ios8 for fear of taking a performance hit. I'm now that fork in the road...

A) Update to the latest version that this version of iOS can support or B) Update to ios9.3.5 (or ios9-something)

Can someone provide details on what I'd be missing out on going with option A? I'm currently on v5.7.1 of the app. 