Windows 10 1909: 7 oddities, quirks and inconsistencies

It's a "feature upgrade" without many new features, shares release documentation with its predecessor, and was ready to go a month before it actually arrived. Yes, Windows 10 1909 is a rare bird indeed.

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Microsoft / Valery Brozhinsky / Fermate / Getty Images

Microsoft last week released Windows 10 version 1909, the strangest feature upgrade yet for the four-year-old operating system.

For a feature upgrade — one of two issued annually — Windows 10 1909 has few new features. And it doesn't upgrade much of anything. Rather, it's Windows 10 1903 — the May release — warmed over. There's so little separating 1903 and its putative successor, 1909, that the latter was identical to the November cumulative update offered to the former on Nov. 12, this month's Patch Tuesday.

So what's the deal?

On one hand, Windows 10 1909 can be seen as Microsoft's solution to the debacle of last year's 1809, an upgrade that, once released, was almost immediately yanked for erasing customer data. That led to months-long delays getting 1809 to users. To get back on its April/October schedule, Microsoft essentially skipped an upgrade by building an un-upgrade.

Another center of speculation contended Microsoft was debuting a new servicing model for Windows 10, one that would generate a feature-rich, and thus major, upgrade in the spring, and a feature-less, service pack-like, and thus minor, update in the fall. Microsoft's most important customers — enterprises and other large organizations — have called on the company to slow its development pace. This would be Microsoft's answer, even though it has declined to say so publicly.

No two ways about it, though, no matter what purpose 1909 served, it's unusual.

To prove that, Computerworld assembled this seven-item collection of overlooked 1909 details.

Two for the price of one

Unlike other feature upgrades, Windows 10 1909 doesn't get its own release paper trail; instead, it shares one with its predecessor from which it was, more or less, cloned.

"The release notes for Windows 10, version 1903 and Windows 10, version 1909 will share an update history page," Microsoft said. "Each release page will contain a list of addressed issues for both 1903 and 1909 versions."

The genesis of the two-in-one release documentation, of course, arose from the fact that 1909 is 1903, albeit one with a few new features. Microsoft put it plainly when it stated, "Windows 10, versions 1903 and 1909 share a common core operating system and an identical set of system files." Only when another update, called an "enablement package," is installed atop 1903 do the features turn on.

As of Nov. 14, the release documentation showed no issues for 1909, but several for 1903. That's because, as Microsoft put it, "The 1909 version will always contain the fixes for 1903; however, 1903 will not contain the fixes for 1909."

Confused? Yeah, we thought so.

One KB to rule them all

Because 1909 and 1903 are one and the same — again, excepting the handful of new features in the former — they share identifiers, notably the KB (for knowledge base) numbers Microsoft assigns for each cumulative update, or CU.

Cumulative updates are those unveiled each month for Windows 10 that contain not only the latest fixes but also all prior fixes for that version. Thus, a November cumulative update for Windows 10 1903 contained the latest fixes as well as all those produced since the version's late-May release.

A key identifier of any update is the KB, the seven-digit number assigned to each update or patch that appears in support documentation and in lists propagated within servicing platforms, including Windows Update, WSUS (Windows Server Update Services) and Configuration Manager. The cumulative update for Windows 10 1809 released on Nov. 12 was marked KB4523205, for example, while 1909's same-day CU was tagged as KB4524570.

The latter KB applied to the CUs for both Windows 10 1903 and 1909, as a glance at the Microsoft Update Catalog confirmed. The only difference maker was the build number — 18362.476 for 1903 and 18363.476 — which changed from the former to the latter only on installation of the cumulative update to Windows 10 1903.

Microsoft had 1909 ready to go in early October

Windows 10 1909, released Nov. 12, was ready to roll as early as Oct. 8, according to Microsoft. "New features in Windows 10, version 1909 were included in the recent monthly quality update for Windows 10, version 1903 (released October 8, 2019), but are currently in a dormant state," the company said in its description of 1909.

All that that October cumulative update — remember, it was issued for Windows 10 1903 — needed to turn itself into Windows 10 1909 Cinderella-like was the "enablement package," which switched on the features. And the only differences between that cumulative update shipped Oct. 8 and November's 1909 were the Windows 10 fixes, security or otherwise, produced during intervening days.

It's still unclear why Microsoft held the release of Windows 10 1909 for a month.

Switch on!

All that stands between a PC running Windows 10 1903 and its transformation into 1909 is what Microsoft dubs an "enablement package." When installed, it activates the small clutch of new features Microsoft stuck in 1909.

Think of the package as the "on" switch (or use the "master switch" label Microsoft coined). Absent the package, a PC running 1903 continues to run 1903. Install the package, and the 1909-only features appear. Magic.

The package will not be available from the Microsoft Update Catalog, but only via Windows Update and WSUS, Microsoft said here. In WSUS, the package is marked as KB4517245. Identified as "Feature Update to Windows 10, version 1909," a name that in the past would evoke a full-OS replacement, the enablement package's small size is the driver of Microsoft's claims that the upgrade from 1903 to 1909 is much faster than prior upgrades.

WSUS for Win10 1909 Microsoft

In Windows Server Update Services (WSUS), the 'enablement package' that turns 1903 into 1909 — and switches on the few features in the latter — is classified as 'Upgrade.'

That's not surprising. Because the few features new to 1909 have already been downloaded to the PC as part of 1903's October or November cumulative updates, there's nothing more than an activation switch to download and install.

For upgrades from 1809 and earlier, the package can't be downloaded separately, Microsoft said. "Instead, it is bundled and automatically included with the feature update to Windows 10, version 1909. Note the installation time is not reduced in this scenario."

On Windows 10 1903, the upgrade to 1909 occupies disk space

Windows 10 1909's disabled features are included in the October and November (and later) cumulative updates (CUs) for Windows 10 1903. They're there, they've just not been switched to the "on" position.

Until the user upgrades a 1903 device to 1909, those features are worthless. Yet they occupy disk space.

"If you choose to keep your devices on Windows 10, version 1903, the disk-space overhead of the dormant/disabled features that are part of the common monthly update is less than 25MB," Microsoft's Wilcox, Oot and Patton said in their Nov. 12 post.

Remember, 1909 is a 30-month upgrade

With all the hoopla about how 1909 is different from past fall feature upgrades, there's been little notice of one major similarity: the length of its support.

"Devices running Windows 10, version 1903 receive 18 months of support. Devices running the Enterprise, IoT Enterprise, or Education editions of Windows 10, version 1909 receive 30 months of support," wrote Wilcox, Oot and Patton.

May 2022 calendar IDG/Gregg Keizer

Windows 10 Enterprise 1909 will be supported with security patches and other bug fixes until May 10, 2022.

Where Windows 10 1903 exits support Dec. 8, 2020, and 1909 does so May 11, 2021, on Home and Pro (for support stretches of 18+ months in both instances), 1909 on Enterprise and Education will receive security updates through May 10, 2022 (or for two-and-a-half years).

The 30-month support timeline — more accurately, the fact that Windows 10 Enterprise customers rely on fall upgrades' extended support — was almost certainly why Microsoft went to the trouble of delivering some kind of refresh, rather than simply skipping one altogether or muddying things even more by adding another 12 months to the lifecycle of, say, Windows 10 1809 after that version's disastrous debut.

Reserved storage? Nope

In January, Microsoft talked up something called Reserved storage, about 7GB of drive space Windows 10 would appropriate to use when processing updates and upgrades. (Updates and upgrades are usually delivered in compressed files — less to download that way — which require drive space to unpack. They also need room to build temp files during the installation process.)

At the time, Microsoft said the storage would be reserved starting with factory-installed copies of Windows 10 1903 or on machines where 1903 and later were clean-installed, such as during a re-image by IT. But Microsoft didn't answer questions posed then, including whether it would requisition the space on PCs upgraded from 1903 to 1909.

Now Microsoft is saying it won't. "Devices updating from a previous version of Windows 10 will not have reserved storage enabled," the company asserted in an online FAQ.

Copyright © 2019 IDG Communications, Inc.

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