Fire OS 5 Developer Preview works with Fire HD 6 and Fire HD 7 tablets (2014 editions), as well as Fire TV and Fire TV Stick.
Please note that after upgrading a device to the Fire OS 5 Developer Preview, rolling back to the production version will factory-reset the device.
We will soon provide our final update of the Fire OS 5 developer preview via an over-the-air update. Once this is applied, you will not be able to roll back the update until we automatically deliver the production Fire OS 5 build to your device (available in the coming weeks).
To remove your device from the Fire OS 5 Developer Preview update pool, please use this form to submit your device information. You have until Sunday, September 27, 2015 at midnight PST to request a roll back.
If you have additional questions, please visit the Developer Preview Knowledge Base, or you may contact us.