Announcing .NET Core 3.1 Preview 3

Rich Lander [MSFT]

Today, we’re announcing .NET Core 3.1 Preview 3. .NET Core 3.1 is 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. We are coming near the end of the 3.1 release and expect to release it in early December.

You can download .NET Core 3.1 Preview 3 on Windows, macOS, and Linux.

ASP.NET Core and EF Core are also releasing updates today.

Visual Studio 16.4 Preview 5 and Visual Studio for Mac 8.4 Preview 2 are also releasing today. They are required updates to use .NET Core 3.1 Preview 3. Visual Studio 16.4 includes .NET Core 3.1, so just updating Visual Studio to 16.4 Preview 5 will give you the latest version of both products.


Go Live

This release is supported in production and you can call Microsoft support with issues.

The site (see version in footer) has been running .NET Core 3.1 in production since Preview 1 without issue and will be updated to Preview 3 shortly. We are confident about the quality of the release.


The primary goal of .NET Core 3.1 is to polish the features and scenarios we delivered in .NET Core 3.0. .NET Core 3.1 will be a long term support (LTS) release, supported for at least 3 years.

The initial download numbers for .NET Core 3.0 are even higher than we expected. We guess that 80-90% (or even higher) of the .NET Core ecosystem will move to .NET Core 3.1 within the first 6 months of the release. We are encouraging everyone to move to the 3.1 release as soon as they can, given that it has a lot of improvements (largely via 3.0) and is the newest LTS release.

Please install and test .NET Core 3.1 Preview 3 and give us feedback.

If you missed it, check out the .NET Core 3.0 announcement from earlier this year.


Discussion is closed. Login to edit/delete existing comments.

  • Nick 0

    Despite Windows Desktop being one of the “big additions in .Net Core 3.0” there’s still no new previews of the WinForms Designer? Is the Designer not scheduled to land until .Net 5 or something? We don’t even have a preview 0.2 yet.

    • Abul Hasan Lakhani 0

      I agree. I have the same concern.. there was no mention of the designer support in any of the talks at the recent MS Ignite 2019.

      • Olia GavryshMicrosoft employee 0

        There actually was! Designer Preview 2 is out and available with the latest Visual Studio Preview. You need to enable it by checking the check box in Tools->Options->Preview Features

        • Nick 0

          Am I looking at the wrong place?

          There is no, 0.2 folder there… is there somewhere else I can get info on what’s new? We don’t have preview 0.1 installed because it’s missing core functionality we need, namely Containers and Resource Files. We’re watching closely (or trying to anyway) to see when those make it in as we are aware that .Net Core 3.x -> .Net 5 is the future of even WinForms development.

    • Raphael Muindi 0

      Use WPF and save yourself the headache, and time!

  • Timothy Liu 0

    .NET Core is perfect, but it’s still not attractive enough to new developers, especially to those who believe algorithms is important than engineering. So, do we have a schedule when .NET Core SDK can have the built-in PriorityQueue πŸ˜‰

    • Richard Garner 0

      I doubt you will see it added as a core collection – but have a look at which provides a whole bunch of collections to extend C#, PriorityQueue included.

  • Rolf Kristensen 0

    Will NetCore 3.1 fix single-file-publish so AppDomain.BaseDirectory matches Process.GetCurrentProcess().MainModule.FileName ?

    See also:

    Right now it ruins the illusion of single-file-publish as AppDomain.BaseDirectory points to a “random” temporary directory.

  • John Tsombakos 0

    Doesn’t look like Visual Studio for Mac 8.4 Preview 5 is actually available – no updates are showing, and the page is not showing that version. Any word when it will be available?

  • Wil Wilder Apaza Bustamante 0

    this comment has been deleted.

    • Severin, Dale 0

      It says in this blog: This release is supported in production and you can call Microsoft support with issues. Is this a GA release?

  • Felix Rabinovich 0

    Everything I read about .NET Core 3 makes me want to upgrade from Core 2 immediately! However, absent some significant changes from Microsoft, it will probably be years! :'( We probably have hundreds of places that EF 2 gave a warning, but EF 3 throws an exception. “Probably” because there is no way to find out, other then during runtime. And unit tests are useless as well. And I just had a conversation with another architect whose organization has exactly same problem.

    I realize, my gripe is about EF, but we are not going to upgrade the rest of .NET Core (even if it is possible) leaving EF behind. Very depressing!

    • Basil Thomas 0

      Yes…you hit the nail on the head: EF is total crap!!
      Should use something like Dapper for a very lightweight ORM especially if you are moving over to a Microservices based architecture.
      Last used EF @ version 4.2 and way too many problems in production.
      Have not looked back since and simple ORM libraries are the way to go especially if you like only use stored procedures and/or the full features available in SQL.

      I have been using .Net Core since 2.1 and will definitely be upgrading to 3.0 once they have production design tools for WinForms, WPF and WinUI in VS2019

      • Wil Wilder Apaza Bustamante 0

        this comment has been deleted.

    • Ian Marteens 0

      Depressing, indeed. EF is not ready for prime time. It was obvious a couple of months ago.

  • 东杰 ηŽ‹ 0

    Is there have a roadmap when will dotnet core 3 support for visual studio 2017 ?

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