Does anyone have document on 'Best Practices and guidelines for Upgrading Enterprise developer and Enterprise server'?

Which versions are you looking to upgrade from and to?

The newer version of Enterprise Developer and Enterprise server now have a preserve config feature.

If if you have 9.0 or above installed and you move to 10.0 or 11.0 and you install in the same COBDIR location as 9.0, then all the config for regions and mfds/escwa settings are preserved.

This does away with a lot of the historical backup and restore steps that where needed.

Hi, 
Also it can be using the review the “Before Upgrading” section in the product documentation. e.g. (assuming you are going to version 10 with Visual Studio 2022 on Windows):
https://docs.rocketsoftware.com/bundle/enterprisedevelopervs2022_ug_100/page/kul1743376525727.html   to be aware of requirements etc.