Microsoft to End Windows 10 Delta Updates

Microsoft plans to end distribution of its monthly Windows 10 "delta updates" starting Feb. 12, 2019, the company announced this week.
Instead of delta updates, Microsoft expects organizations to use "express updates" each month for Windows 10. With express updates, only the Windows 10 software changes (or "differentials") will get delivered to an organization's computing environment from Microsoft's content delivery network.
A delta update is a type of monthly quality update for Windows 10 that just delivers changes to existing OS components, but it will only install if the previous month's quality update is present. In contrast, with an express update, the content delivery network pushes down both missing and new quality update elements, regardless of the computing environment's monthly Windows 10 patch status.

Delta Updates explained
Microsoft has introduced cumulative updates in Windows 10. If such an update is installed, the installer checks which patches are missing on the machine and installs them. As a result, the size of a cumulative update increases with each patchday. The package must contain all patches so that the update installer can make up for the missing patches on the machine.
For Windows 10 the Microsoft developers have therefore relied on the solution with the so-called’Delta Updates’. The delta updates only contain the patches of the previous month and no longer the complete update history of the relevant Windows 10 build. This should reduce the size of the update packages by up to 40 % (see the following diagram).

Source: Microsoft

The use of express updates can potentially lower the bandwidth hits that organizations face each month with Windows 10 quality updates. Quality updates are "cumulative updates," which means they contain past OS updates along with new updates for existing Windows 10 components.
Microsoft estimates that its monthly cumulative updates for Windows 10 start out at around 100MB to 200MB in size but then expand to 1GB to 1.2GB in size in about six to eight months' time. Microsoft also has "full updates" for Windows 10, which are more than 1GB in size.

Microsoft sees express updates as being a better distribution mechanism for monthly quality updates. It's only continuing to distribute the delta updates until the Feb. 12 end date because it'll give "companies and third-party update management tools time to implement support for express updates," the announcement indicated.

In addition to delivering monthly quality updates, Microsoft has feature updates for Windows 10. They're different from the monthly quality updates because they bring new features to the OS instead of just updating existing OS components. Feature updates are new OS versions that typically arrive twice per year, in the spring and the fall.

Explained: Windows 10 quality updates & the end of delta updates: https://t.co/FvjmeqSxNr pic.twitter.com/6HDZ43uhCi

— Windows IT Pro (@MSWindowsITPro) July 11, 2018

Microsoft Delta updates were introduced with Windows 10 Creators Update and are available for the following versions.
-Windows 10, Version 1607
-Windows 10, Version 1703
-Windows 10, Version 1709
-Windows 10, Version 1803
Delta updates will also be available for Windows 10 (October update), which will be released in autumn.

The end of delta updates
Now Mike Benson from Microsoft announced last Wednesday in the article Windows 10 quality updates explained & the end of delta updates the end of the above mentioned delta updates. First, he discusses the different models for update packages (Full Update, Delta Update and Express Update) in enterprise environments. Under WSUS, for example, there are still express updates that should install faster (and according to the graphics should also be more compact). He then writes that Microsoft will stop the delta updates.

The background: The concept of express updates allows to generate differential downloads for each component in full update. The generated downloads are based on the update history of the machine and the differential updates on the Microsoft update servers. This allows the scope of a full update to be distributed as a package, but the size can be significantly reduced by differential delivery (only changes to files are delivered).
For example, the latest cumulative May 2018 update (called Latest Cumulative Update, LCU) contains the file tcpip.sys. Microsoft now wants to create a differential for all tcpip.sys file changes from April to May, from March to May and from the original version to May.

A device that uses Express Updates uses the network protocol to determine optimal differences between the installed version and the modifications on the Microsoft server. Then Windows Update will download only what you need. Microsoft writes that this is usually about 150-200 MB per month. The more current a device is, the smaller the size of the differential download.
Devices that are directly connected to Windows Server Update Services (WSUS), System Center Configuration Manager, or a third-party update manager that supports express updates receive these smaller payloads.

As Express Update Support for third-party update managers has been available for over a year, Microsoft plans to discontinue the delivery of Delta updates. Starting February 12, 2019, Microsoft will end its practice of creating delta updates for all versions of Windows 10. Express updates are much smaller, and simplifying cumulative options reduces complexity for IT administrators. You can read more details, including the user discussion, in Microsoft’s article.

July 15, 2018