Hello,
Thank you for posting in Microsoft Q&A.
Based on the description, I understand your question is related to Exchange update.
To update your Exchange Server 2016 (Version 15.1 Build 1779.2), you need to download and install Cumulative Update 23 (CU23). This is the latest cumulative update available for Exchange Server 2016.
https://www.microsoft.com/en-us/download/details.aspx?id=104132
Have a nice day.
Best Regards,
Molly
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