The current Windows 10 Mobile Fast Ring release, Build 14271, is only available for commercially released Windows 10 devices like the Lumia 550, 650, 950 and 950 XL plus the Xiaomi Mi4 and the Alcatel Onetouch Fierce XL.
Although that has frustrated users of Windows Phone 8.1 devices it allows Microsoft to focus their testing on newer devices.
However, today with the release of Windows 10 Mobile Build 10586.122 for the Current Branch (CB) for Insiders which is a Cumulative Update, the company has added the following devices for CB testing:
- MCJ Madosma Q501
- BLU Win HD W510U
- BLU Win HD LTE X150Q
- Alcatel Onetouch Fierce XL
Please take note - this new Slow and Preview Ring build are for CB testers only - if you are in the Fast Ring and not receiving development branch builds you can join one of these rings using the Windows Insider app and gain access to this build.
If you are running Windows Phone 8.1 on a supported device then Microsoft would like you to run this upgrade because it has improvements to the upgrade experience between Windows Phone 8.1 and Windows 10 Mobile and they can only be experienced by going through that upgrade path. If you are very enthusiastic about helping Microsoft test this scenario then you could also reset your supported device back to Windows Phone 8.1 using the Windows Device Recovery Tool (WDRT) and getting access to these builds with the Windows Insider app to test the upgrade path.
Since this update is being pushed out to Slow and Preview Ring users it is an indication that it should be fairly stable and less buggy than Fast Ring builds.
In fact, there are not listed known issues for this build - only a list of fixes:
- Improved Kanji input experience while using Continuum.
- Improved the speed in which thumbnails appear for portrait videos.
- Improved Internet Sharing on select mobile network configurations.
- Fixed an issue in Microsoft Edge that prevented Word Flow input on some sites.
- Fixed an issue that previously prevented the option to “Close all Tabs” in Microsoft Edge from closing all open tabs.
- Improved IMS registration on select mobile network configurations.
- Fixed an issue where adding your MSA during OOBE would fail and prevent the account from being re-added after the failure.
- Improved the email sync experiences when connecting to Wi-Fi networks with a captive portal.
- Improved data connection profiles for dual SIM devices.
- Updated background processing of multiple changes to improve battery life of devices.
- Improved quality of video record to SD memory cards.
- Improved video recording audio in some cases.
- Improved overall OS reliability, including reliability of the Start screen, app updates, and the Windows Feedback app
- Improved Alarm reliability.
Let us know how you plan to test this new build on your device(s).