The current version of the iOS app is not installable on a first-generation iPad, as it requires a newer version of the operating system than can be used on this device.
If it is *completely impossible* to make the app backward-compatible for some reason (I confess I cannot imagine any such reason, but I am not an iOS developer; maybe there is a good reason) then olders version of the app (which does work, albeit it crashes all the damn time) should not nag me to update to the unusable latest version if they are running on an older OS.