.NET Framework 4.5.2, 4.6, 4.6.1 will reach End of Support on April 26, 2022

Jamshed Damkewala

Jamshed

.NET Framework 4.5.2, 4.6, and 4.6.1 will reach end of support* on April 26, 2022. After this date, we will no longer provide updates including security fixes or technical support for these versions.

Customers currently using .NET Framework 4.5.2, 4.6, or 4.6.1 need to update their deployed runtime to a more recent version – at least .NET Framework 4.6.2 before April 26, 2022 – in order to continue to receive updates and technical support.

*Windows 10 Enterprise LTSC 2015 shipped with .NET Framework 4.6 built into the OS. This OS version is a long-term servicing channel (LTSC) release. We will continue to support .NET Framework 4.6 on Windows 10 Enterprise LTSC 2015 through end of support of the OS version (October 2025).

There is no change to the support timelines for any other .NET Framework version, including .NET Framework 3.5 SP1, which will continue to be supported as documented on our .NET Framework Lifecycle FAQ.

Why are we doing this?

The .NET Framework was previously digitally signed using certificates that use the Secure Hash Algorithm 1 (SHA-1). SHA-1 is a legacy cryptographic hashing algorithm that is no longer deemed secure. We are retiring content that were signed using digital certificates that used SHA-1 to support evolving industry standards.

After looking at download and usage data across the different versions of .NET Framework, we found that updating .NET Framework 4.6.2 and newer versions to support newer digital certificates (for the installers) would satisfy the vast majority (98%) of users without them needing to make a change. The small set of users using .NET Framework 4.5.2, 4.6, or 4.6.1 will need to upgrade to a later .NET Framework version to stay supported. Applications do not need to be recompiled. Given the nature of this change, we decided that targeting .NET Framework 4.6.2 and later was the best balance of support and effort.

See this support article on retiring SHA-1 content for more information.

When .NET Framework 4.5.2, 4.6, and 4.6.1 reach end of support, applications that run on top of these versions will continue to run. Starting May 2022, we won’t be issuing security updates for .NET Framework 4.5.2, 4.6, and 4.6.1 when we issue these security updates for .NET Framework 4.6.2 and later versions. This means that starting May 2022, if a computer has .NET Framework 4.5.2, 4.6, or 4.6.1 installed, it may be unsecure. Additionally, if you run into any issue and need technical support, you will be asked to first upgrade to a supported version.

.NET Framework 4.6.2 shipped nearly 5 years ago, and .NET Framework 4.8 shipped 2 years ago, so both versions are solid, stable runtimes for your applications. .NET Framework 4.6.2 and 4.8 are highly compatible in-place updates (replacements) for .NET 4.5.2, 4.6, and 4.6.1 and broadly deployed to hundreds of millions of computers via Windows Update (WU). If your computer is configured to take the latest updates from WU your application is likely already running on .NET Framework 4.8.

If you have not deployed .NET Framework 4.6.2 or a later version yet, you only need to update the runtime on which the application is running to a minimum version of 4.6.2 to stay supported. If your application was built to target .NET Framework 4 – 4.6.1, it should continue to run on .NET Framework 4.6.2 and later without any changes in most cases. There is no need for you to retarget or recompile against .NET Framework 4.6.2. That said, we strongly recommend you validate that the functionality of your app is unaffected when running on the newer runtime version before you deploy the updated runtime in your production environment.

Resources

Here are some other resources you may find helpful:

We are committed to help you ensure your apps work on the latest versions of our software. Should you have any questions that remain unanswered, we’re here to help. You should engage with Microsoft Support through your regular channels for a resolution.

Additionally, if you run into compatibility or app issues as you transition to .NET Framework 4.6.2 or later, there’s App Assure. We’ll help you resolve compatibility issues at no additional cost. You can contact App Assure for remediation support or by email if you experience any challenges submitting your request (ACHELP@microsoft.com).

You may also want to look at this FAQ for more detailed answers or questions not covered in this post.

Closing

.NET Framework 4.5.2, 4.6, and 4.6.1 will be reaching end of support on April 26, 2022 and after this date we will no longer provide updates including security fixes or technical support for these versions. We strongly recommend you migrate your applications to at least .NET Framework 4.6.2 or higher before this date.

20 comments

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  • Θοδωρής Τσιρπάνης
    Θοδωρής Τσιρπάνης

    Great news that old .NET Framework versions are getting unsupported.

    Just curious however, why didn’t you just sign these installers again with SHA-256? I guess there were implications with timestamping?

    • Jamshed Damkewala
      Jamshed DamkewalaMicrosoft employee

      The problem is fairly complex since it not just the outermost bundle that needed to be re-signed, these products carry multiple installers, CABs, and other artifacts wrapped inside and each of those may carry more. The work to re-sign was somewhat simpler for newer .NET Framework versions due to changes that happened over the 7 year period between .NET Framework 4.5.2 and now. So as I said in the main post, after reviewing telemetry for the various versions we determined this was the best balance between providing support and the corresponding effort. And yes, time-stamping was also a factor.

  • Avatar
    Jozef Izso

    Hi Jamshed,
    this breaks any installer/bootstrapper created by WiX Toolset. Is this the expected outcome?

    As a developer of installers, I would expect you announce this way more earlier so we can prepare our toolsets and build tools.

    Right now, our installers are partially broken and the repair functionality is broken totally. Despite we did full QA cycle on the installer.

    This information should have been published a year ago. You cannot publish such critical change on a day when you break everybody’s installers.

      • Avatar
        Jozef Izso

        .NET Framework 4.5.2, 4.6, 4.6.1 installers do not expire in Apr 2022. The .NET Framework 4.5.2, 4.6, 4.6.1 products won’t receive any security updates after the date.

        Many applications install the .NET as a dependency which is downloaded and the package must be verified. Microsoft published new, incompatible packages on existing URLs which effectively brakes any installer which verifies downloaded payload. This was done without any notice as the breaking packages are already published and none of the existing ISV could prepared a fixed releases of their software.

        • Jamshed Damkewala
          Jamshed DamkewalaMicrosoft employee

          @Josef, I’m sorry you’re experiencing the break due to our rebuild of the installers, unfortunately there was no way to avoid the rebuild. The FAQ linked from the post touches upon this scenario and documents the new public key for our installers. Your bootstrapper XML needs to be updated to replace the old public key with this one. I understand its a simple change, yet its impactful when something that was working breaks and needs to be updated.

          The quickest workaround in the immediate term is updating your bootstrapper yourself, in the near future we will also ship an updated ClickOnce bootstrapper in a VS update which will allow developers to use VS to simply rebuild their ClickOnce bootstrapper or Visual Studio Installer Project (which also internally uses the CO bootstrapper) to update their .NET Framework redistributable reference to the updated installers.

          • Avatar
            Jozef Izso

            I think this is such a breaking change for any software, application and/or installer out there, that this should be marked in big red BREAKING CHANGE at the top of the blog post.

            And I’m just baffled you did not communicate breaking change with developers in any way and you don’t have your own tools ready, not to mention the negligence of the WiX Toolset open source project where you did not provide new and valid definitions for the .NET Framework setup files.

          • Jamshed Damkewala
            Jamshed DamkewalaMicrosoft employee

            Also meant to add: we do update the ClickOnce bootstrapper for each .NET Framework version that ships in Visual Studio, but this has traditionally lagged the .NET release by some weeks/months. We’ve considered this lag acceptable given that anyone can with fairly limited effort create a bootstrapper for any custom product (including the .NET Framework redistributable) pretty quickly using docs like the instructions here for creating your own ClickOnce bootstrapper: https://docs.microsoft.com/en-us/visualstudio/deployment/creating-bootstrapper-packages?view=vs-2019.

  • Avatar
    qw ...

    The maximum installable .net framework version for Windows 10 v1507/LTSB2015 is 4.6.2, so what are the support and updates for netfx462 installed on LTSB2015?

    • Jamshed Damkewala
      Jamshed DamkewalaMicrosoft employee

      .NET 4.6.2 will continue to be supported beyond April 2022, there is no end of support date planned for 4.6.2. The only versions that will go out of support in April 2022 are .NET 4.5.2, 4.6, and 4.6.1.

  • Avatar
    TSX

    Assuming that NF 4.8 is final version of NF, and will last as Windows last, do it (NF 4.8) will be supported (fixes and security) as long as Windows is supported ?
    Or maybe NF 4.8 support will be ceased, as with these verions mentioned in post.

  • Avatar
    当空 皓月

    The maximum installable .net framework version for Windows Server 2008 SP2 is .net Framework 4.6, so what are the support and updates for netfx46 installed on Windows Server 2008 SP2 with purchased Extended Security Updates?

    • Avatar
      kai x

      Today is June’s Patch Tuesday. This morning I searched Windows’s updates in Catalog and found “Security Update for .net framework 4.6 on Windows Server 2008 SP2” changed to “Security Update for .net framework 4.6.2 on Windows Server 2008 SP2”, but I clearly remembered the latest version of netfx can be installed on Windows Vista/Server 2008 SP2 is 4.6.1. So I tried to run netfx 4.6.2 setup on Windows Server 2008 SP2 and it said the OS is not supported. Then I redownloaded netfx 4.6.2, 4.7 & 4.8 from official website and tried to install them. 4.6.2, which is resigned by sha2 only, can be installed properly (for my surprise!!! but 4.7/4.8 still can’t be supported). After the installation completed, I installed the latest security update rollup for netfx 4.6.2 and tried to run some software that requires netfx 4.0 and later, but strangely, they still say netfx 4.0 is not installed. I uninstalled 4.6.2 and installed 4.6.1, then these software ran properly immediately. So, how to explain this? How to solve this problem on Windows Server 2008 SP2?

    • Avatar
      kai x

      This evening I tested another Windows Server 2008 SP2 with all security updates installed. I installed netfx 4.6.2 on it and then the latest monthly rollup. Then I tried to run these software that have netfx problems this morning. They ran smoothly but some little problems happened. For example, Office Tool Plus 7.6 can’t connect to the Internet to download Office files. After I uninstalled netfx monthly rollup(installed netfx was still 4.6.2), these little problems didn’t appear anymore. But if I install any monthly rollup for it, these problems appear again. How to solve this?