Background I have spent the past few days converting some of my ASP.NET Core 2.2 projects to 3.0 which just came out 3 days ago. I'm using Razor, SignalR and Dapper in some of these projects and I knew the conversion won't be straight forward since a lot of the core libraries have undergone major re-work. The easiest thing you can do to get started is to create a new project using one of the existing project templates in Visual Studio and compare its settings with your own project. This should give you a good idea on what to change in order to get your project going again. The official migration guide from Microsoft also has a lot of useful information. It shouldn't take too long before most people work out all the necessary changes needed to start their projects again. So the main focus of this blog is to share some of the "less obvious" breaking changes I have encountered during my upgrade and provide their solutions. Hopefully you and other developers