The page https://dynamobim.org/download/ is just showing a download link for https://s3-us-west-2.amazonaws.com/dyn-builds-data/DynamoCoreRuntime2.1.0.zip
What happened to the Windows installer? If that’s not available, what is the procedure to upgrade manually? Overwrite all the files in <C:\Program Files\Autodesk\Revit 2020\AddIns\DynamoForRevit> ?
Revit 2020 has all Dynamo builds managed by Revit now - there is no updating Dynamo for Revit 2020 outside of Revit 2020’s point releases.
That installer is specifically for testing future work in Sandbox, as noted here: A new way to get Dynamo Sandbox - Dynamo BIM
If you want any Revit interaction, the latest un-bound release of Dynamo for Revit is version 2.0.2, which works with Revit 2017, 2018, and 2019 (but not 2020).
Is there still a Windows installer, somewhere?
For what exactly?
If the latest versions need to be installed on users’ computers.
I am going to assume you want Dynamo for Revit as that’s what I have seen you use the most of. As I explained above, the method for getting the latest for all Revit versions after 2019 is going to be update Revit. So:
Dynamo for Revit 2020: Install Revit and all updates.
Dynamo for Revit 2017-2019, go to https://dynamobuilds.com/, and install the latest DynamoInstall, currently 2.0.2.