[Zubersoft]

If you are using version 3.3.7 of MobileSheets, that is very out-of-date, as the latest version is 3.8.13. It's fine to stick on an older version if you want, but over time, you may encounter issues potentially with cloud services or due to changes to the operating system. If you also don't update the OS, then you should be relatively safe to stick on whatever version you want.

I don't think there are any issues moving MobileSheets data between those two devices as long as you are running the same version of MobileSheets on both (you can check this under Settings->About).

Mike