@Anonymous , Thanks for posting in our Q&A. From your description, I know you have deployed a profile which upgrade old windows version to Windows 10 21H2 and set the feature update deferral period to 0 days. The policy is worked, and some windows machines are updated . But the speed is slow, you want to know if there is a way to speed up the progress. If there is any misunderstanding, feel free to let us know.
For those computers that are not updated, I suggest you check if the policy is applied on the computer in Intune portal, if the registry keys in the following location are changed on the device side:
For more information, here is an article for reference:
In Intune, there’s another option 'Deadline for feature updates” which specific the number of days a user has before feature updates are installed on their devices automatically. We can try to set the minimum value as 2 days to see if it can help.
In Fact, Windows Update Ring policies only define an update strategy, they don’t actually provide the update infrastructure itself. This means you need to use your existing update solution such as Windows Update or WSUS to obtain the actual updates. However, if the policy is applied but the devices are still not updated, you can open a new thread and add tag "windows10-general" to involve windows support to see if there’s any method to speed the update progress on windows update side.
Hope the above information can help.
If the answer is helpful, please click "Accept Answer" and kindly upvote it. If you have extra questions about this answer, please click "Comment".
Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.