News

Microsoft Moves Windows 10 April 2018 Update to 'Semiannual Channel' Stage

• By Kurt Mackie
• 07/13/2018

Windows 10 version 1803 (also known as the April 2018 Update and previously code-named "Redstone 4") is now in the semiannual channel (SAC) release stage, Microsoft said this week, though what that designation means for organizations is a little unclear.

Normally, IT pros might take the SAC designation to mean that they can begin deploying Windows 10 version 1803 in their organizations. However, Microsoft appears to be shifting how it describes its update model.

An SAC release used to be referred to as the "current branch for business" (CBB) release. In past Microsoft formulations, an SAC release (or CBB) was deemed to be an important milestone for IT pros managing Windows 10 environments. According to those descriptions, it represented a well-tested operating system update that was suitable for deployment in computing environments. Organizations using management software to control the arrival of Windows 10 updates were to consider deploying SAC releases.

Of course, the SAC label was just a descriptor for organizations about the readiness state of a major Windows 10 feature update, suggesting that fixes to software flaws had been applied by Microsoft. Organizations typically waited for an SAC release to arrive prior to deployment to avoid experiencing those software flaws.  

Current Model
The current Windows 10 feature update model is shifting in terms of Microsoft's descriptions, but it appears to have the following release types:

• SAC: A recommended update for organizations.
• "Fully Available": An update state that's undocumented by Microsoft, although it was formerly identified as being equivalent to the SAC release.
• SAC-T: An update designated for testing by organizations, with the "T" standing for "targeted."
• LTSB: A long-term servicing branch release that's not recommended for use by organizations (it's conceived for devices that can't undergo frequent updates).

On June 14, Microsoft declared Windows 10 version 1803 to be fully available, which was described as being "the final phase of our rollout process" by John Cable, director of program management for Windows Servicing and Delivery, who indicated that the update would be delivered automatically to end users through Windows Update. Of course, the final phase of Windows 10 feature update rollouts previously had been described as an SAC release.

In January, Michael Niehaus, formerly director of product marketing for Microsoft's Windows Commercial group and now a principal program manager on the "modern deployment team" at Microsoft, had explained that full availability was essentially the same thing as the SAC release, except that Microsoft was also trying to signal availability for its consumer users.

In the case of Windows 10 version 1803, the actual SAC release was documented by Microsoft as arriving on July 10, about one month later than the fully available release. So, the SAC release and the fully available release apparently weren't the same thing.

What's Going On?
Microsoft hasn't clarified this confusion. Possibly, things are advancing somewhat, and we'll see a future Windows 10 feature update model described as follows:

• SAC, which will be the old SAC-T release.
• "Fully Available," which will be the old SAC release.
• LTSB, which won't have any change.

My speculation above is based on recent Microsoft descriptions. In June, John Wilcox of Microsoft had suggested that Microsoft was planning to drop its SAC-T designation from future Windows 10 update descriptions. Organizations should have been testing and deploying the SAC-T releases all along instead of waiting for the SAC release, Wilcox had argued.

Microsoft's documentation still has the SAC-T lingo in it, but the semantics seem to be changing. Here's how Microsoft's "Overview of Windows as a Service" document, updated on June 1, described it:

Organizations are expected to initiate targeted deployment on Semi-Annual Channel releases, while after about 4 months, we will announce broad deployment readiness, indicating that Microsoft, independent software vendors (ISVs), partners, and customers believe that the release is ready for broad deployment. Each feature update release will be supported and updated for 18 months from the time of its release.

That description appears to suggest that there will just be an SAC release and a fully available release in the near future under the Windows 10 feature update model. Organizations will be expected to deploy an SAC release, which earlier had gone by the SAC-T name. Basically, they'll be deploying test releases.

Microsoft didn't respond to questions, so its plans are unclear at present. However, the language associated with the Windows 10 update model seems to be in flux.