In a multi-part announcement spread across three blog posts, Microsoft has again given its Windows 10 update model a shake. Here's what the changes mean.

Microsoft has again given its Windows 10 update model a furious shake, voiding one of the foundational concepts of the โWindows as a serviceโ (WaaS) strategy.
In a multi-part announcement spread across three blog posts, Microsoft on July 1 said it had begun testing of the next Windows 10 feature upgrade, which it has codenamed 19H2 but by the companyโs four-digit (yymm) labeling will be tagged with 1909 when it ships.
The first build of 19H2/1909 was released that same day to Windows Insider participants who set their PCs to receive the โSlowโ ring versions. Insider will continue to deliver previews of 20H1 โ the feature upgrade that will likely be dubbed 2003 to show it was completed in March 2020 โ to testers on the โFastโ ring, as has been the case since February, when Microsoft debuted next yearโs edition.
Although Microsoft did not put the announcementโs biggest news in plain English โ instead relying on some marketing-speak, coded language and at least one new acronym โ that news was impossible to miss.
Microsoft has ditched the idea of generating more than one feature upgrade annually, and will instead produce a single substantial refresh, apparently each spring.
Say what?
โThe next feature update for Windows 10 (known in the Windows Insider Program as 19H2) will be a scoped set of features for select performance improvements, enterprise features and quality enhancements,โ John Cable, director of program management for the Windows servicing and delivery team, wrote in a July 1 post to a company blog.
In Cableโs post and also in one by John Wilcox, a Microsoft WaaS evangelist, the company representatives laid out the changes. Because they underplayed the import of those alterations to the Windows 10 maintenance model, weโll explain what will be different and more importantly, what that means to the hundreds of millions of users of that OS.
Now we know what happened to 1909
In mid-February, Microsoft spurned precedence and started seeding the most adventurous Insider beta testers with builds from what it called the 20H1, or first half, 2020, development branch. Previously, Skip Ahead had been used to get the next feature upgrade to testers โ that would have been the fall upgrade, 1909, or in Microsoftโs code, 19H2 โ but instead it jumped over 1909.
To explain the detour, Microsoft said: โSome things we are working on in 20H1 require a longer lead time.โ While that may well have been true, it was an unsatisfactory justification, what with Microsoftโs recognition that regularity is something corporate customers value. Microsoft did promise that 19H2/1909 would be released, if not as usual, then โlater this spring.โ
That was what Microsoft on Monday handed to Insiders on the Slow ring.
Weeks ago, Computerworld wondered what had happened to 1909 as Microsoft kept its lips zipped. The experts who weighed in rejected rumors that Microsoft would skip the upgrade, perhaps to get back on track after delays to the two previous. They each nailed it with their prognostication, with one predicting a shift to annual upgrades, the other forecasting a shift in schedule to Major in the spring, Minor in the fall.
On the surface, then, Microsoft remained committed to a twice-a-year slate, one itโs hewn to since 2017, postponements and re-releases and all.
But thatโs not quite the truth.
Deciphering the announcement, part 1
โ19H2 will be a scoped release with a smaller set of enhancements focused primarily on select performance improvements, enterprise features, and quality enhancements,โ said Wilcox in his post, which was directed at commercial customers, Microsoftโs most important (emphasis added).
The sentence, almost a word-for-word repeat of Cableโs post โ and thus certainly part of Microsoftโs corporate messaging โ requires unpacking.
By scoped release, Wilcox seemed to be using the first word to define a limited release, one that has had strict boundaries set regarding the to-be-included functions and delivery date. (This is the first time Computerworld recalls Microsoft using the phrase โscoped release,โ but it can be found here and there in other software developersโ commentary.) That analysis was bolstered by Wilcox saying, โGiven this limited scope, we will deliver the 19H2 in a new wayโฆ.โ in the next paragraph (emphasis added).
His calling out smaller set and select are additional proof points that the fallโs release would play the minor role to the spring releaseโs major. Also worth noting are two of the three things listed as part of 19H2 โ performance improvements and quality enhancements โ almost always prominently appear in software developersโ descriptions of their less-ambitious upgrades because, well, they donโt have new features to trumpet.
Bottom line: 19H2 (or 1909, take your pick) will be a minor release that includes few, if any, new features.
Deciphering the announcement, part 2
โTo deliver these updates in a less disruptive fashion, we will deliver this feature update in a new way, using servicing technology (like the monthly update process) for customers running the May 2019 Update who choose to update to the new release,โ stated Cable (emphasis added). โIn other words, anyone running the May 2019 Update and updating to the new release will have a far faster update experience because the update will install like a monthly update.โ
This was the second important part of the announcement. Again, unpacking is necessary.
Because 19H2/1909 will be a minor refresh of Windows 10, it will be significantly smaller than past feature upgrades, which have been full OS replacements tipping the scales between 3GB and 5GB (4.6GB for the 64-bit version of 1903, for instance). Microsoft acknowledged that 19H2 will not be an OS replacement, at least when using this faster servicing approach, because itโs restricting that to those running 1903 (the May 2019 Update, which went final in late May).
That means 19H2 will be much more like one of the cumulative updates issued several times monthly to Windows 10, which build on the already-in-place OS but do not replace it. (The most notable update is Patch Tuesdayโs, the โqualityโ update โ Microsoftโs word โ that includes vulnerability patches and all kinds of non-security fixes.)
The monthly cumulative updates โ and 19H2, too, when installed by 1903 and 1903 only โ are small, and thus fast to download and install, because they include only the changes from the prior code. Over the last two years, Microsoft worked on reducing the size of the cumulative updates โ as well as the number of update sizes โ most recently with those deployed by 1809, the October 2018 Update that ended up delayed until early 2019.
Itโs worth repeating this: Windows 10 19H2/1909 will be an update to Windows 10 1903, not a true feature upgrade as customers have known them.
Thatโs why the analogy to โservice packsโ made by many observers resonates. For the forgetful, service packs were the cumulative updates of the past โ Windows 7 and earlier โ that integrated already-issued fixes with the original code. They rarely included new features. Microsoft last issued one in February 2011, when it released Windows 7โs Service Pack 1, or SP1; Windows 7 SP1 is the currently-supported version of the 2009 operating system, set to drop from support in January 2020.
Windows 10 19H2/1909 will include all that was in Windows 10 1903, plus additional bug fixes, performance improvements and stability enhancements, but few if any new features. Sounds like a service pack to us, too.
Deciphering the announcement, part 3
โWe will begin releasing 19H2 builds to Windows Insiders in the Slow ring starting today ((July 1)), with new features being offered in future Insider builds as they are ready,โ Cable wrote in his post (emphasis added). โSome Insiders may not see the new features right away as we are using a controlled feature rollout (CFR) to gain better feedback on overall build quality.โ
This process was both clear in its purpose and vague in its execution. It also represents a mix of old and new. First, the clear: previews of 19H2/1909 shown to Insider participants will include off-by-default features that can be, but not necessarily will be, switched โonโ at some later date. Each feature will first be tested with a small subgroup of Insiders; as bugs are uncovered and quashed, and Microsoft becomes convinced the feature works as intended without significant negative side effects, others will be added to the test pool. At some point, presumably, everyone has it enabled by default.
This โcontrolled feature rolloutโ procedure is something Microsoft already uses in a much more general fashion when it favors the PCs it believes will not balk at installing a feature OS upgrade. But CFR, named that or not, has long been a hallmark of some browser makers โ notably Google (Chrome) and Mozilla (Firefox) โ who tuck new features into an update but then donโt immediately turn them on, sometimes waiting days or weeks to do so, other times slowing adding enabling more usersโ copies over time in the hope that any bug wonโt afflict everyone.
Microsoftโs CFR closely resembles Chromeโs and Firefoxโs deliberate โswitch onโ approaches, even to how they turn on a feature or option. โSpecific to CFRs, we may ship features in these updates turned off by default and turn them on independently of bits getting downloaded to Insidersโ PCs,โ Microsoftโs Wilcox added.
Thatโs how Chrome and Mozilla do it, too.
Secondly, however, thereโs the vague: Although Microsoft said it would use CFR while it runs 19H2/1909 through Insider-based testing, it said nothing of relying on the rollout tactic at or after launch.
CFR-generated prudence would seem to be a smart move for any new feature in 19H2/1909, seeing as the truly-new would have little time with Insiders (July 1 through a September debut, or two months and change). Or, if the new feature(s) in 19H2/1909 are actually items brought forward from 20H1 testing (the Insider focus since February), a leisurely distribution would also be a good idea, since the integration with the earlier upgrade might have been run through little or no testing.
On the other hand, CFR-based activation of a deployed 19H2/1909, especially on corporate PCs, could be a pain point for IT administrators if Microsoft, not themselves, were in charge of deciding when a feature pops on. Enterprise IT does not like surprises, one reason why resistance quickly grew against Windows 10โs twice-annual upgrade cadence and 18-month support lifecycle.
Questions remain, but hereโs the bottom line so far
Not surprisingly, there are unanswered questions about the new process. Itโs likely answers wonโt be known until this fall or even later than that, after 19H2/1909 wraps up Insider testing and reaches customers. But Computerworld believes thereโs enough information now to paint a rough picture of how the changes reflect the evolving Windows 10 feature upgrade process.
- The fall upgrade โ 1909 โ will be a delimited update, akin to a monthly cumulative release rather than a full feature upgrade. It will sport performance and reliability improvements and perhaps a few new features. It will not be an OS replacement, as all previous upgrades have been.
- 1909 will be deployable via Windows Update or Windows Update for Business using a servicing mechanism similar to that used by the monthly updates. Via those update services, 1909 will only be available to users already running 1903, aka May 2019 Update.
- For commercial customers running 1809 (October 2018 Update) or earlier, the upgrade process remains unchanged. โYou will have the option to update to 19H2 just as you did with previous releases,โ Microsoft said, meaning that 1909 will be deployable using, say, Windows Server Update Services (WSUS) or System Center Configuration Manager (SCCM).
- Windows 10 1909 is, more than anything, a โservice packโ for 1903. For users who did not โ and will not โ run 1903, Windows 10 1909 is essentially 1903 plus some improvements.
- Because of the above โ most importantly the lack of new features โ itโs difficult to view 1909 as a credible feature upgrade on its own. Microsoft has, then, reduced its 2019 output to one feature upgrade (1903) and one service pack for that feature upgrade (1909).
- Itโs implausible that Microsoft has crafted this as a one-off, in other words 1909-as-service-pack for a one-time rollout (perhaps to simply make up the time lost to delays by 1809 and 1903). This major (spring release) and very minor (fall release) will be the new normal going forward and last โฆ well, until Microsoft again changes its mind.
There are other aspects of the latest upend to Windows upgrades, which Computerworld covers in this companion piece, that will influence enterprise scheduling and affect Microsoftโs penchant for pressing consumers to act as testers for commercial customers.