Upgrading the csproj file
There is a stark difference in the way Visual Studio and Azure handles
.csproj files depending on how "new" they are.
Microsoft did a revamp of their
.csproj files from 2017 onwards. This version of
.csproj is automatically created if you create a .NET or a .NET Core application when you use Visual Studio 2017 or later.
But for .NET Framework applications, the old version of
.csproj is still used. This is very apparent in Revit and ETABS addins.
This article is pretty useful if you are thinking of migrating across from the old to the new:
Old csproj to new csproj: Visual Studio 2017 upgrade guide
It even shows you how to migrate, what to keep and what to throw.
Most of the time, I had to pretty much start over and I think that is better because you get total control on how the project behaves.