Hi @David Moon ,
At first, for 1903 upgrading to 1909, we could install the enablement package instead of installing the feature update. This does not require another September 2020 update for 1909 build.
Windows 10, versions 1903 and 1909 share a common core operating system with an identical set of system files. Therefore, 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 in an inactive and dormant state. These new features will remain dormant until they are turned on through the “enablement package,” a small, quick-to-install “master switch” that activates the Windows 10, version 1909 features.
The enablement package is a great option for installing a scoped feature update like Windows 10, version 1909 as it enables an update from version 1903 to version 1909 with a single restart, reducing update downtime. This enables devices to take advantage of new features now.
Here is the article we could refer to:
https://support.microsoft.com/en-us/help/4517245/feature-update-via-windows-10-version-1909-enablement-package
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