Microsoft to dump Windows 10's smaller delta updates

The company has decided they're no longer needed because express updates can fill the bill. The delta updates will end in February 2019.

Gregg Keizer Jul 19th 2018
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Microsoft will stop serving one of three types of Windows 10 updates, contending that the updates have been superseded by an even small and more efficient format.

Delta updates are due to disappear early next year, Microsoft said, with their demise effective Feb. 12, 2019, that month's Patch Tuesday. Two formats will then remain: Full updates and express updates.

Delta updates are those that include only the components that have changed since the previous month's update. Because delta updates include the full component that changed - say, the Notepad application - not only the individual files that make up the component, they are larger than express updates, which deliver only changed files. The bottom line, and what enterprise IT is most interested in, is that express updates are smaller than delta updates, which are in turn smaller than full updates.

According to Mike Benson, a member of the Windows team responsible for crafting updates, an express update typically weighs in at 150MB to 200MB, compared to a delta update's larger 300MB to 500MB. Put another way, express updates are between 33% and 70% smaller than delta updates.

With that the case, why does Microsoft bother providing delta updates?

"Delta updates were originally created because the express update protocol was only available to devices connecting directly to Windows Update or Windows Server Update Services," Benson wrote in a July 11 post to a company blog.

In January 2017, Microsoft gave third-party update management vendors access to the express protocol but continued to offer delta updates to "give companies and third-party update management tools time to implement support" for the format, Benson explained.

Stopping delta updates in February - the last ones will be issued in January - makes sense, Benson said, because third-party patch products will have had two years to get with the express program. And culling the update formats, he added, "will reduce complexity for IT administrators."