Mind you, I don’t recommend that you install 1909 just yet. Like any Windows update, it needs time to ferment before consuming. Version 1909 has a particularly paltry — almost non-existent — list of worthwhile new features.
Some of the rollout details have come into focus.
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Microsoft has long referred to an “enablement package” that turns a 1903 installation into a 1909 installation. In a nutshell, Win10 version 1903 already has all of the 1909 bits, waiting to be lit up like unplugged lights on a Christmas tree. The 1909 upgrade simply plugs in the lights. As Microsoft puts it on the Windows IT Pro Blog:
Windows 10, versions 1903 and 1909 share a common core operating system with an identical set of system files. As a result, the new features in Windows 10, version 1909 were included in the latest monthly quality update for Windows 10, version 1903 (released October 8, 2019), but are currently in a dormant/disabled state. These new features will remain dormant until they are turned on via an “enablement package,” a small, quick-to-install “master switch” that simply activates the Windows 10, version 1909 features.
Moving from 1903 to 1909
The path from Win10 version 1903 to 1909 goes through a very genteel gateway. If you’re running Win10 1903, you only get the 1909 lights turned on (at least at this point) if you explicitly click on the Download and install now prompt.
1903 after reboot installing 449Microsoft
That prompt appears (Start > Settings > Update & Security) after you install this month’s Win10 1903 cumulative update, KB 4524570. As I explained earlier this month, you’re under no obligation to click the "Download and install now" link.
The November cumulative update for 1903 gets applied in the usual way, which means you can defer it, pause it, or throttle it by using a metered connection — all standard tools of the trade for delaying Windows patches.
[ Further reading: Windows 10: A guide to the updates ]
(Note: For those still confused by the difference between “Pause” and “Defer” in Win10 1903 Pro, you aren’t alone. As @b states, the Windows updater respects both settings, so you won’t get updated until both the Pause and the Defer periods have elapsed.)
In addition, @abbodi86 confirms that the "Download and install now" link will only appear after a Win10 1903 Pro machine has gone beyond its “feature update deferral” setting. So for those using Win10 1903 Pro, you won’t even see the "Download and install now" link until the specified number of days have passed.
1903 update deferrals zeroMicrosoft
In addition, you won’t see the "Download and install now" link appear on machines that have been blocked because of identified incompatibilities with either hardware or software.
Admins will be happy to know that the “enablement package” is available in WSUS and SCCM, so it can be readily blocked and released using your usual methods.
As best I can tell, that’s the whole story for those already on Win10 1903. It’s a good story — an abrupt and most welcome departure from the push and shove reputation Win10 upgrades have so annoyingly earned.
Moving from 1809 to 1909
If you’re running Win10 version 1809, you’re subject to slightly different rules. Microsoft hasn’t published the rules, but this is the best we’ve been able to discern.
With both Win10 1809 Pro and Home, if you have the May 2019 cumulative update (KB 4497934) or a later cumulative update installed, you see an invitation to Download and install 1909 now, as shown in the earlier screenshot. There are three exceptions:
If your machine is being blocked because of a known hardware or software incompatibility. You won’t receive the Download and install now invitation until your computer passes muster.
With Win10 1809 Pro, the feature upgrade deferral days must have passed, starting on Nov. 12 — the day 1909 was released. Once you’re beyond the feature deferral days, you get the Download and install now invitation.
With either 1809 Pro or Home, if you click Check for updates, you’ll likely be upgraded to 1909. No invitation. Just a whoosh and a whimper. As a service, doncha know.
The 1909 upgrade bottom line
All of this represents a huge improvement over earlier Win10 upgrades. Night and day.
If you start from Win10 1903, you have complete control over when you're upgraded to Win10 1909. Remarkably, that's true for both Home and Pro (and Enterprise and Education) versions.
If you start from Win10 1809 Pro, the details are a bit more difficult but in the end you, too, have easy control over the upgrade.
If you start from Win10 1809 Home, life's