Hotpatch compliance detection and cumulative update equivalency

Hello Domic,

Thank you very much for the information, I had discussed same with third party vendor but as per vendor their logic rely on https://www.catalog.update.microsoft.com/ and registry keys, Microsoft does not provide hotpatch for download in https://www.catalog.update.microsoft.com/ hence they can not update their metadata/logic, as they rely on Microsoft Catalog and Registry entry status.

Please suggest in this case what is recommended, who can help.

Hello,

What you are seeing is a known limitation in how compliance tools detect servicing state when Hotpatch is used. Hotpatch updates (like KB5120994 in your example) keep the OS current without installing the full cumulative update package (KB5121003). Windows Update correctly reports the system as up to date, but third‑party compliance tools often rely on registry keys or the installed update list, which only reflect the cumulative update KB. Because Hotpatch does not lay down the same KB markers, the compliance tool interprets the system as missing the CU even though it is fully serviced.

From Microsoft’s servicing perspective, this is expected behavior. Hotpatch replaces the need for the monthly cumulative update, but compliance tools that are not Hotpatch‑aware will always show a gap. There is no supported way to force registry entries or manually inject CU KB markers, because that would break servicing consistency. The only reliable fix is for the compliance vendor to update their catalog logic to recognize Hotpatch metadata. Microsoft has already documented that Hotpatch systems should be considered compliant if Windows Update shows “up to date,” even if the CU KB is not listed.

For now, the best practice is to continue using native Windows Update or WSUS reporting for compliance validation, and work with your third‑party vendor to ensure their detection logic supports Hotpatch. Attempting to disable Hotpatch or push full CU packages just to satisfy the tool will create unnecessary bandwidth and servicing overhead, especially with the 4–5 GB package sizes you mentioned.

I hope you've found something useful here. If it helps you get more insight into the issue, it's appreciated to accept the answer. Should you have more questions, feel free to leave a message. Have a nice day!

Domic Vo.