The list of devices that will be further supported for Windows 10 Mobile Redstone preview is not different from the devices eligible to receive the Windows 10 Mobile upgrade. Logic is simple for Microsoft!! The devices that will not receive Windows 10 Mobile now will have to sit out of Redstone Preview. But if you have a supported device as shown in the list below and you are an Insider already, you don’t need to do anything and you are already enrolled to the Redstone Preview.
Q: If I already have the current Windows 10 Mobile Insider Preview build and my device is on the updated list of supported devices for the Windows Insider Program, do I need to do anything?
A: No action is required on your part. As a Windows Insider you have the latest build and do not need to downgrade to Windows Phone 8.1 to receive any updates. Your device is up-to-date. If you no longer want to receive Windows Insider Preview builds on a particular supported device, you may switch to Production and await future retail updates or move to the Release Preview ring to receive early app updates
Supported phones for Windows 10 Mobile Insider Preview
We’re working to get more Windows Phone models supported worldwide. Download the Windows Insider app, and when your phone is supported you’ll be able to sign in with the same Microsoft account you used to join the Windows Insider Program. Windows 10 Mobile Insider Preview currently works with the following phones—as long as they have at least 8 GB of storage, Windows Phone 8.1 was already installed on the phone at the time of purchase, and the version number is 8.10.14219.341 or earlier: