Earlier this week, Michael Fortin, Corporate Vice President, Windows published a blog post about Windows 10 monthly security and quality updates. The post details the different type of monthly updates, from the “B” releases happening on Patch Tuesday, to optional “C” and “D” patches that Microsoft ships later in the month.
Today, an article from PCWorld put an emphasis on these optional releases, highlighting the fact that these C and D updates are “beta code.” In the own words of Microsoft's Michael Fortin, “the intent of these releases is to provide visibility into, and enable testing of, the non-security fixes that will be included in the next Update Tuesday release.”
We cover every new Windows 10 build on OnMSFT, and we always mention it when they come with known issues. Even Patch Tuesday updates sometimes come with known issues, so it’s not just “C” and “D” updates that can be problematic.
However, what the PCWorld articled failed to mention is that Microsoft has been releasing preview-quality updates for quite a long time. To our knowledge, the company changed its update schedule starting with Windows 10 version 1703 (aka the Creators Update). This is what Microsoft’s Michael Niehaud explained at the time:
Based on feedback from customers, we are making some adjustments to the updates that we are releasing for Windows 10, version 1703 (also known as the “Creators Update”). With these changes, we will routinely offer one (or sometimes more than one) additional update each month. These additional cumulative updates will contain only new non-security updates, so they will be considered “Updates” in WSUS and Configuration Manager.
So yes, Microsoft has been releasing more than one new build every month for quite some time now, and the optional quality updates that are released later in the month eventually end up in the Patch Tuesday for the following month. All Windows 10 updates, including these optional updates are cumulative, which means that they include all previously released fixes.
Microsoft re-explained its Windows 10 update servicing cadence back in August of this year, making it clear that the optional “C” and “D” updates are only available for seekers. Additionally, the company said that it may sometimes ship “out-of-band releases” to address critical bugs that cannot wait for the next Patch Tuesday. “These are reserved for situations where devices must be updated immediately either to fix security vulnerabilities or to solve a quality issues impacting many devices,” the blog post explained.
In case the August blog post wasn’t enough, the company also published the following 3 minutes video explaining everything about Windows 10 monthly updates:
To conclude, yes, Microsoft has been releasing optional quality updates since the release of Windows 10 version 1703 last year. These updates are a preview of upcoming quality fixes, and they’re only available for users who check for updates in Windows Update. These patches eventually end up in the following Patch Tuesday, which will be pushed to all Windows 10 users.
Again, the optional C and D updates sometimes come with known issues, but that's also often the case with the monthly Patch Tuesday updates. In the past, Microsoft used the Windows Insider Release Preview Ring to test all new Windows 10 builds in the production ring, but the company has been doing this less consistently over time. Anyway, it may be a good idea to keep the Windows 10 update history page in your bookmarks, but you can also count on us to tell you all the details about new Windows 10 patches.