Today Microsoft released .NET Core 3.1 which is a LTS (long-term support). The current .NET Core 3.0.1 version will be supported by Microsoft until 2020-03-03.
We decided that the best move for Radzen would be to require .NET Core 3.1. This will ship with Radzen 2.40.0 which will release later today.
What does that mean for existing Radzen Blazor applications
Radzen users will see a similar message when they open a Radzen Blazor application and they don't have .NET Core 3.1 installed.
The solution is to download and install .NET Core 3.1 and then restart Radzen.
What about Radzen.Blazor - the Radzen Blazor Components
We released a new major version 2.0.x which is based on .NET Core 3.1. Before using it make sure you have upgraded your non-Radzen Blazor applications to 3.1. Check the official blog post here.