Microsoft has just released Windows 10 Mobile build 10166 to Fast ring members. Right on the heels of the Windows 10 build 10166 for the PC, Microsoft has ended the week with a new build for mobile users as well. Included in this build are a number of small changes, and feature tweaks. Additionally, Microsoft has ironed out most of the known issues from build 10149, as the focus of the past few mobile builds has been on core quality.
Microsoft fixed the issue that made the lock screen appear frozen, resolved the issues with unlocking phones after putting in the PIN, and also improved the reliability of app downloads and updates from the Store. They have also removed the old Store, and dropped the beta tag on the new one.
The update is now available, so if you are a member of the Fast ring, be sure to download it now.
Source: Windows Blog