Microsoft today promised it will reduce the size of Windows 10 "feature updates," the upgrades the company issues once or twice a year.

"One of the biggest community and customer benefits of UUP is the reduction you'll see in download size on PCs," said Bill Karagounis, director of program management, in a post to a company blog Friday.

UUP stands for "Unified Update Platform," Microsoft's name for its new update delivery technologies.

So far, all Windows 10 feature updates have been issued as full replacements -- an OS re-install -- with resulting downloads of 3GB to 4GB. That will continue with the next refresh, which last month Microsoft dubbed Creators Update, that is expected in March 2017.

The one after Creators Update, however, should be more than a third smaller, said Karagounis, because UUP will deliver only "differential" updates. "A differential download package contains only the changes that have been made since the last time you updated your device, rather than a full build," Karagounis said.

Change-only updates are often called "delta" updates.

UUP will also shift some of the update evaluation process -- deciding what a device requires, if anything -- from the PC to Microsoft's Windows Update service. "This will lead to faster checks for update operations," Karagounis added.

Microsoft will begin using UUP to distribute new builds to Windows Insider participants' PCs later this year, in line with the company's practice of trying new technologies on the several million testers before offering them to the general Windows 10 population.

Although Microsoft has pledged to issue two Windows 10 feature updates in 2017, it has neither named nor scheduled the post-Creators update that will first use UUP.