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 version release history tracker Windows 10 Creators Update new features

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. All content on this site is provided with no warranties, express or implied. Use any information at your own risk. Always backup of your device and files before making any changes. Privacy policy info.