This Is the current OS I'm running, though I'm not completely sure how to check if it's compatible. My kindle fire 7 is in fact used for e-books, though I've personally never used it for that, and I've downloaded countless other apps on here that seem to work, most of them from Google play store (which is something kindle isn't really supposed to have) or from other sources. I think I've had one other situation where I've downloaded a game from Itch.io and it did the same thing as it did with this app.