Microsoft has pushed out a new build of Windows 10 Mobile users and this time, it is build 10149; the download is now available to Fast Ring users in the Insider program.
The download is available now by going to Settings - > Update and Security -> Phone Update and then having your device look for the new build. This release is only for Fast Ring users.
Microsoft has pointed out that this build still has the missing post-upgrade migration screen, and as such, the lock screen will appear frozen for up to 10 minutes after installing. If you do restart your phone before this process finishes, you will end up in a 'funky state' as Microsoft calls it, so sit back and relax.
As usual, you should only install this on a backup device as these builds have been known to have quite a few issues with them.