Eyefi won't send me an older version of the app because the only way to install it would be to have a jailbroken ipod.
So, If I had installed the older version legitimately when it was available, I would be ok. Since the old version of the app is no longer available, I'm SOL because my ipod can only run 4.2.1 which is no longer supported by the latest version.
This is a really bad way to treat a customer. It's easy for them to just email the file or make it available for download somewhere.
Be careful when buying Eyefi products. I am not happy with their support.