Install KB5000871 Update on Exchange 2016

Marcus Wong Theen Nam 1,066 Reputation points

I have 3 Exchange servers 2016 CU17 in the environment. I am about to update one of the server to CU 19 and then install the KB5000871. My question is, before installing the CU 19, normally I will do a Windows Update to make my server up-to-date. So during the Windows Update, will it download the KB5000871 and install? If yes, do I still need to install it manually again after I install CU 19?

Perhaps anyone could advise on this. Or can I just skip the Windows Update and straight to the CU 19 installation? Although I know this is not recommended by Microsoft but just wondering if it will cause any issues.

Thank you.

Exchange Server Management
Exchange Server Management
Exchange Server: A family of Microsoft client/server messaging and collaboration software.Management: The act or process of organizing, handling, directing or controlling something.
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Accepted answer
  1. Andy David - MVP 120.5K Reputation points MVP

    It wont be in Windows Update and since there is no patch for CU17, it couldnt be installed anyway since it wouldnt apply

    I always apply Windows Updates first,
    then reboot
    Then the CU with an elevated prompt
    then reboot
    Then install 5000871 with an elevated prompt

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  1. Yuki Sun-MSFT 29,351 Reputation points

    Hi @MarcusWong-9726,

    Although according to the update in KB5000871, an additional series of security updates are being produced by Microsoft for older CUs which include Exchange 2016 CU17, these update packages are only a temporary measure and are available only through the Microsoft Download Center (not on Microsoft Update). Therefore, KB5000871 won't be installed during the Windows Update.

    That being said, for your current scenario, it's suggested to follow the recommended path below, that is, installing the latest supported CU (CU19) and then apply the applicable SUs:

    Reference: March 2021 Exchange Server Security Updates for older Cumulative Updates of Exchange Server.

    Furthermore, the official blog below contains information and resources that can help you plan your updates, troubleshoot problems, and help you with mitigations, investigation, and remediation of the vulnerabilities, hopefully you can find it helpful:

    Released: March 2021 Exchange Server Security Updates

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  2. Marcus Wong Theen Nam 1,066 Reputation points


    One of the servers have been patched successfully and no issues were encountered. Thanks for the assistance.


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