Microsoft has released Windows 10 Mobile officially to the selected devices yesterday. The update is now rolling out to existing Windows 8.1 devices. Along with that Microsoft announced new insider redstone build too. Windows 10 redstone preview build 14291 is now available for both Mobile devices and PC. It brings many new features in PC version, especially the expected extension support on Edge browser.
The update in case of Mobile devices is only available for devices that shipped with windows 10 Mobile but other devices will be added in coming weeks as per Microsoft. You can read what has changed or fixed in Mobile Build 14291 by clicking here.