Microsoft has issued another late afternoon (Redmond time) Fast Ring Insider build, this time for Windows 10 Mobile updating it to 15063.2, and it contains a single "fix," which isn't much of a fix after all:
UPDATE 3/28: We have released Windows 10 Insider Preview Build 15063.2 for Mobile to Windows Insiders in the Fast ring. This build includes a single fix to enable the ability to update to Build 15063 from the Windows 10 Anniversary Update (Build 14393) on Windows phones.
The fix won't do anything for Windows 10 Mobile Insiders, but will allow users on the Windows 10 Mobile Anniversary Update (build 14393) to upgrade to the final Creators Update build, which they should be able to do very, very soon now.
In the interest of being dedicated and awesome Insiders, you should download and install the build as soon as possible, just to make sure everything works, so get to downloading!