Just curious what dependencies are causing you so many issues?

Skype for Business SDKs, primarily. That is basically our business. Teams is the new hotness, but doesn't have any Api access.

Makes sense. They keep claiming Skype for Business is dead, but Teams in my opinion is very far away from being a realistic replacement.

I've not been very impressed with the desktop application at all (although the web-site is "fine").

I have deployed teams in 'island' mode for our org and I'm a bit disappointed with it - we've had firewall problems with external attendees and have had to switch back to skype for that case. A few users have had the teams client crash repeatedly during calls. I don't see how anyone will move to it with issues like these.

Could you encapsulate these dependencies into a separate service? I did that a while ago in a similar situation but as always it depends on your specific situation.

One big one that isn't mentioned yet is Entity Framework. Now, before you say "But there's an Entity Framework Core!" it's not the same at all. It has nowhere near the same amount of features and performance nor integration into Visual Studio like EF has. This is the biggest blocker for us to move completely to .NET Core.

EF6 is part of .NET Core 3.0: https://blogs.msdn.microsoft.com/dotnet/2018/10/04/update-on...

Partially, there is no guarantee of all EF 6 related tooling like the data designers will fully work with the Core 3.0, just the actual code execution.