Update on this:
We’re currently deploying a fix, so that players who have unintentionally been updated to version 6.2 can go back to version 6.1. This means if you’ve been updated to 6.2 on your Amazon Store devices like your fire tablet then you can go back to playing on your other devices that have 6.1 installed.
We have sent a message to make sure version 6.1 gets put back onto the Amazon store. The 6.2 update won’t be playable any more and there will be a message to go back to version 6.1 in the meantime.
You may need to reinstall on your Fire tablet once we have put version 6.1 back on the Amazon Store.
I will most likely have more news about this issue tomorrow morning (as it’s 7pm here now).
Sorry for this issue.
EDIT: You can get version 6.1 from this Help Center article in the meantime, just tag me if you need any help.