Microsoft has just initiated the rollout for a new build of Windows 10 Mobile for fast ring insiders, which includes a whole bunch of changes and stability improvements over build 10080. Todays build is 10136, and is only being offered to fast ring insiders who downgraded back to Windows Phone 8.1 due to a bug with 10080. Those on 10080 will have to wait for the next build before they can upgrade.
Build 10136 includes more improvements to the user-experience, including changes to the Settings app and a few built in apps too. There have been thousands of code changes between build 10080 and 10136, so hopefully this build is a lot more stable and usable.
Stick around at WinBeta for an in-depth look at all the new changes found within this build. The new build is rolling out now so make sure you check for updates and get downloading. If you're yet to see the download, give it time as the update is still propagating and will take some time to reach everyone. Will you be downloading this new build?