News

Semiannual Channel Updates Ending for Windows Server Products

• By Kurt Mackie
• 07/28/2021

Microsoft has published a timeline signaling an end to its semiannual channel (SAC) updates for its supported Windows Server products.

Update 7/30: This article was updated to correct a misunderstanding that Azure Stack HCI would get SAC releases. It's not getting them.

SAC releases, which arrive twice per year, are generally going away. Instead, Microsoft plans to release long-term servicing channel (LTSC) updates for its Windows Server products. These LTSC releases are new Windows Server bits that will arrive "every 2-3 years," per this June 24-dated Microsoft document describing features that were removed from Windows Server.

The end dates for current SAC releases can be found in this "Windows Server Release Information" document, dated July 26. For instance, organizations using the Windows Server version 20H2 SAC (released in October 2020) will be supported until May 10, 2022 on that channel release. Organizations using Windows Server 20H2 SAC presumably must jump to a new LTSC release before the May 10, 2022 deadline to have a Windows Server product that continues to get patch support.

Azure Stack HCI and Windows Server Updates
Microsoft's "Release Information" document mentioned an apparent exception to the SAC policy change for users of Windows Server on Azure Stack HCI, which is Microsoft's Azure-in-a-box implementation for installation on an organization's servers. However, there is no exception. SAC is dead across the board for Windows Server.

Here's Microsoft's misleading sentence:

"The Semi-Annual Channel in previous versions of Windows Server focused on containers and microservices, and that innovation will continue with Azure Stack HCI," the document tersely explained.

That statement actually just means that Microsoft's "innovation" for Windows Server will still arrive for Windows Server when it gets used with Azure Stack HCI. However, these Windows Server updates aren't SAC releases as implied by Microsoft's sentence. Azure Stack HCI gets updates once per year, per this Microsoft document description, so the updates don't arrive as "semiannual" channel updates. The Azure Stack HCI product follows an update model that's more like the Azure update model.

Here's how the Azure Stack HCI update model was explained by Jim Gaynor, an analyst with independent consultancy Directions on Microsoft, via e-mail:

When it comes to servicing Azure Stack HCI as an OS, it's serviced as a "Modern Lifecycle" product -- neither SAC or LTSC. It receives regular (roughly monthly) quality and security updates just like Windows Server, with annual feature updates targeted for the second half of the year. Each annual feature update is supported for two years -- effectively giving customers a year to move to a new version before the previous one leaves support.

In essence, SAC is dead for Windows Server in all instances, even Azure Stack HCI, because Azure Stack HCI doesn't follow the SAC update model.

Windows Server LTSCs Get 10 Years of Support
Microsoft's LTSC releases for Windows Server products will have "5 years of mainstream support and 5 years of extended support," per the "Release Information" document.

That 5+5 support period is reminiscent of the traditional support time allowed under Microsoft's Fixed Lifecycle Support policy, but it apparently happens under the more tenuous Modern Lifecycle Support policy. For instance, Microsoft's "Release Information" document contains a note stating that "Windows Server, version 1803 and later are governed by the Modern Lifecycle Policy."

LTSC Support Halved for Windows 10 and Office
In contrast to Windows Server, LTSC support will get truncated for other Microsoft products. Microsoft had announced in February that it planned to halve the traditional 10 years of support for the next Windows 10 and Office LTSC releases, for instance.

Despite the halving of support for the next Windows 10 and Office LTSC releases, Microsoft has indicated that they will be governed under the Fixed Lifecycle Support policy. It's an oddity because the Fixed Lifecycle Support period typically has lasted 10 years, not five years.

Microsoft also plans to switch organizations over to subscription-based licensing with the releases of its newest application server products. The first one to pop up in that respect is SharePoint Server Subscription Edition, which is currently at the preview stage. No licensing and support details were described, though.

Windows Server 2022 Is LTSC Only
Windows Server 2022, Microsoft's latest server product, is expected to arrive commercially in the second half of 2021. It will just get LTSC updates, Microsoft's "Release Information" document explained.

Windows Server 2022 is currently at the "release-to-manufacturing" stage, having been previewed in March. Microsoft described its main features in late June, but didn't mention at the time that it would be an LTSC-only product.

SAC's Quiet Death
SAC's disappearing role for Windows Server implementations isn't exactly news. The information was tucked away in a June 24 document. However, it was just noticed on Wednesday by veteran Microsoft reported Mary Jo Foley, in this July 28 ZDNet article.

Microsoft had modeled Windows Server updates after its Windows 10 biannual feature update model. However, it may have become apparent to Microsoft at some point that new Windows Server features and frequent updates really weren't what most organizations wanted.

The dropping of SAC for LTSC with Windows Server was "not surprising," according to Gaynor.

"The last few SAC releases have had very little 'new' to them, save incremental container-related enhancements," Gaynor stated in a July 27 Twitter post. "Yet all Azure services that support Windows Server containers have required LTSC versions for base OS images."