Microsoft rolled out its latest batch of cumulative updates from November 12, 2019, along with the 1909 feature build update. KB4524570 is one of the latest cumulative updates for Windows 10 build versions 1909 and 1903 at the time of writing. Although not listed on that update’s page, KB4524570 provides a fix for a Windows 10 update deferral bug.
The Windows Update tab in Settings usually includes deferral settings for users to select under Advanced options (in Win 10 Pro, S, and Enterprise editions). Those settings are listed under the subheading: Choose when updates are installed. The options enable users to defer, or delay, feature and cumulative updates for a specified number of days. Users can delay a feature update by up to one year with those settings.
However, some users have stated in forums that they cannot find their update deferral options. Thus, the deferral options disappeared for those users. That was due to a Windows 10 1903 deferral bug.
Users could still adjust deferral options via the registry. This requires that users edit the DeferFeatureUpdatesPeriodInDays and DeferQualityUpdatesPeriodInDays values with the Registry Editor. Those are DWORDs for the HKEY_LOCAL_MACHINESOFTWAREMicrosoftWindowsUpdateUXSettings key.
Now, however, users have discovered the KB452570 update fixes the deferral bug. Thus, that update restores the deferral options for users even though the update’s page does not mention a deferral bug fix. The KB452570 page cites a Keyboard Lockdown Subsystem fix, for filter key input, as one of its key changes.
Therefore, it comes as something of a surprise that the deferral settings have now been restored in Windows 10 1903 and 1909. So, Pro, Enterprise, and S users can once again delay Windows 10 updates via Advanced options in Settings. Users can check if they have received the KB452570 update by clicking View update history on the Windows Update tab in Settings. If it’s not listed there, click the Check for updates button.
Update: Microsoft updated its cumulative update support page to reflect the changes:
Microsoft has released an update directly to the Windows Update client to improve reliability. Any device running Windows 10 configured to receive updates automatically from Windows Update, including Enterprise and Pro editions, will be offered the latest Windows 10 feature update based on device compatibility and Windows Update for Business deferral policy.