Gas Cubby 2.7 not working on Iphone 4S

[CHS32]

I have an Iphone 4S, an Iphone 5, and two IPADS, a version 2 and 3. The new 2.7 version of Gas Cubby is working on the newer IPAD (I haven't checked the older one) and the Iphone 5, but just opens to a blank screen on the 4S, then shuts down after a few seconds. This is with the latest 2.7 version. This was working fine before I upgraded all to IOS 8 and now all have the latest IOS version as of this date (8.0.2).

Thoughts?

Thanks
Charlie