Microsoft is rolling out Windows 10 build 15063.2 for mobile devices enrolled in the Fast ring. This is the first release the company makes available as an incremental update, instead of a completely new build as the Windows 10 Creators Update is now finalized and only days from general availability.
The cumulative update doesn’t introduce new features, and it brings only one fix to enable devices running Windows 10 Mobile version 1607 (Anniversary Update) to successfully upgrade to version 1703 (Creators Update).
You can also use the following resources:
Windows 10 build 15063.2 for Mobile is available immediately through the Fast ring. It’ll download and install automatically on your device, but you can always force the update from Settings > Update & security > Windows Update and clicking the Check for updates button.
Update, March 29, 2017: Microsoft is now rolling out Windows 10 build 15063.2 to the Slow ring.