Hi @MichaelRobb,
Thanks for the status update.
> I will note that the upgrade instructions mentions to not uninstall previous version and that the install will upgrade. nothing more.
The help documentation you're referring to, is meant for ArcGIS Monitor 2023. So the statement is true, when upgrading from Monitor 2023.0, 2023.1, or 2023.2 - you can directly upgrade to 2023.3. It does not refer to Monitor 10.8.1.
Note we address moving from Monitor 10.8.1 to 2023 in question 6 in the FAQ I mentioned previously.
FYI, the help documentation for ArcGIS Monitor 10.8.1 is separate and can be found here.
Hope this helps and happy holidays,