Our plan is to support Kindle and any other suitable android device which may not have access to the Play Store. Our tentative plan is to provide a web download, just as Glenn has suggested.
IFly demands OS 4.0.x or higher, and a relatively new devices (2 yrs or less, typically), and a few GB's of space, to hold a subset of our Data (500MB to 10GB range depending upon the data you download).
In the meantime, if you don't have access to Google's Play Store, and want to try out 8.1.25b, please send me an email, and I'll send you a copy of the APK. brian@adventurepilot.com