iOs version?

It used to work on iOS 6.x, now it says 7.x required. When I try to open the app, it puts me in a continuous update loop that recognizes I have an older iOS version but says "download" the older version, yet can never proceed to the game. Now Im wary of whether I should spend the money on the regular Tetris game (which by the way still says iOS 6.x on the info page in iTunes). It might get upped too, and render my purchase obsolete. I wish this was still back compatible so my kids could still play on my old iPhone that has become their mini gaming device.

Robbx213 about TETRIS®