This is useful if you have an add-in that doesn’t work on a current version of Office. I created an SCCM package to perform the downgrade.
:: Enable Office Updates
“C:\Program Files\Common Files\microsoft shared\ClickToRun\officec2rclient.exe” /changesetting UpdatesEnabled=True
:: Perform Downgrade
“C:\Program Files\Common Files\microsoft shared\ClickToRun\officec2rclient.exe” /update user updatetoversion=16.0.17726.20160 DisplayLevel=false
:: Disable Office Updates
“C:\Program Files\Common Files\microsoft shared\ClickToRun\officec2rclient.exe” /changesetting UpdatesEnabled=False
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If you have any issues, make sure Windows Updates is working. I noticed on one of my lab machines Windows Updates was returning an error, thus preventing the downgrade. All Office apps should be closed before beginning as well.