Can the Upgrade Assistant be used against a .NET Framework 2 project?

[Rod-at-DOH]

I'm on a team that's migrating our source code out of an old TFS on-prem, to GitHub. Consequently, I've reviewed about 200 TFVC projects. The majority of our code is written using .NET Framework 4.5.2. However, this week I discovered several assemblies all written using .NET Framework 2! Some of these assemblies are from a third-party vendor we used in the past. For whatever reason, the apps that use these assemblies have never been upgraded from .NET Framework 2. And even on NuGet, where I've found some legacy assemblies from the vendor, they only goes back as far as .NET Framework 4.5.2.

So, that makes me wonder, is .NET Framework 2 so old that even the Upgrade Assistant won't upgrade it?