Major Windows 10 updates, including this summer's Anniversary Update and next year's Creators Update, are distributed as essentially full operating system installs. The downloads are around 4GB, and installing them performs a complete in-place upgrade to Windows.

That is set to change as Microsoft rolls out what it calls its Unified Update Platform (UUP). Major upgrades will be shipped as differential updates, where only the differences between the currently installed version and the newly installed version need to be downloaded. The company estimates that this will result in major version upgrades being around 35 percent smaller.

UUP should also make checking for updates faster, as more of the computational workload to figure out the patches that a system needs will be handled in the cloud rather than on the client.

In making this change, some differences between the Windows 10 Mobile and Windows 10 PC update process are being eliminated. Currently the desktop platform can generally upgrade from any patch level to the latest version in one shot; on mobile, sometimes multiple updates are required, with two separate download, install, and reboot processes.

End-users on stable builds of Windows won't see this change take effect until after the Creators Update; the client-side infrastructure necessary to support these differential updates will be a part of that release. Insiders, however, who regularly perform major version updates (as every new Insider build is installed as an in-place upgrade) will begin seeing the improvements much sooner. Mobile releases will enable UUP updating starting with today's build 14959, with the technology coming to PC builds a little later in the year, followed by Windows IoT and Windows for HoloLens. Excluded from this is Xbox, which will retain its own update process.

The visible end-user impact of UUP should be minimal; Windows Update will still look the same, and the overall patching and updating policy isn't changing. It will just be faster and use less data.