Microsoft has released the second preview release of .NET Core 3.1 for Windows, macOS, and Linux

Here the announcement:

Announcing .NET Core 3.1 Preview 2 | .NET Blog

Today, we’re announcing .NET Core 3.1 Preview 2. .NET Core 3.1 will be a small and short release focused on key improvements in Blazor and Windows desktop, the two big additions in .NET Core 3.0.. It will be a long term support (LTS) release with an expected final ship date of December 2019.

Announcing .NET Core 3.1 Preview 2 | .NET Blog