skip to Main Content

Exchange 2013 .NET Framework compatibility

Let’s learn more about Exchange 2013 .NET Framework compatibility. We like to update .NET Framework in Exchange Server 2013 because we want to run an Exchange Cumulative Update. What is the best approach to update .NET Framework in Exchange Server? Do we first update .NET Framework, or do we run the Exchange Cumulative Update? These questions are being asked a lot.

A lot of Exchange admins have seen Exchange Servers breaking and not working after a Cumulative Update. In this article, you will learn about Exchange 2013 .NET Framework compatibility.

It’s important to know that .NET Framework is a must for Exchange Server. When installing Cumulative Updates on Exchange 2013, we sometimes have to update .NET Framework. That is not always the case. Sometimes you can run the Cumulative Update without updating .NET Framework. Yes, we can download .NET Framework for free.

What Microsoft is saying about .NET Framework:

When upgrading Exchange Server from an unsupported CU to the current CU and no intermediate CUs are available, you should first upgrade to the latest version of .NET that’s supported by your version of Exchange Server and then immediately upgrade to the current CU. This method doesn’t replace the need to keep your Exchange servers updated on the latest supported CU. Microsoft does not claim that an upgrade failure will not occur using this method, resulting in the need to contact Microsoft Support Services.

Keep .NET Framework and Exchange Server 2013 up to date

Keep your Exchange Server 2013 up to date so that you don’t have to carry out a longer update path. I recommend downloading the Exchange CU ISO when it’s available and save it to the hard disk. Microsoft does remove older Exchange CUs when newer versions are released. When saving the Exchange CU ISO, you can always carry out the upgrade path. You can use an unofficial website to download an older Exchange CU.

Exchange 2013 .NET Framework compatibility path

Don’t immediately update when a .NET Framework version or Exchange Server version is released. Always wait and check if bugs are rising. Don’t forget to always test the Exchange Server in a test environment before updating it in production.

I made a flowchart that will show the procedure on how to update .NET Framework and Exchange Server Cumulative Update.

Exchange 2013 .NET Framework compatibility

To keep it simple, keep these two steps in mind when planning the update path:

  1. Update to the last Exchange version that is supported by the .NET Framework (blue arrow)
  2. Update to the last .NET Framework that is supported for the Exchange Server (green arrow)

Keep updating till you’re on the version that you want to be. It will most likely be the last released Exchange version.

Let’s have an example with the following company called EXOIP. The company is currently running Exchange Server 2013 CU10 and .NET Framework 4.5.1. They want to update to the latest Exchange Server version, which is Exchange Server 2013 CU23. Let’s have a look at how to do that without breaking the Exchange Server.

Exchange 2013 .NET Framework compatibility upgrade path
  1. Upgrade to Exchange 2013 CU15
  2. Upgrade .NET Framework to 4.6.2
  3. Upgrade to Exchange 2013 CU20
  4. Upgrade .NET Framework to 4.7.1
  5. Upgrade to Exchange 2013 CU22
  6. Upgrade .NET Framework to 4.7.2
  7. Upgrade to Exchange 2013 CU23
  8. Upgrade .NET Framework to 4.8

Use the given flowchart. It’s easy to follow the update path for Exchange Server Cumulative Update and .NET Framework. Do not hesitate to use the comments below to ask any questions if you have them!

Articles that are interesting to read:


In this article, you learned how to use the Exchange 2013 .NET Framework compatibility flowchart. Are you going to update .NET Framework in Exchange Server 2013? I recommend using the Exchange 2013 .NET Framework compatibility flowchart. Save the Cumulative Updates when the Exchange CU ISO’s are available for download, as Microsoft will delete them after a newer version comes out. You might need it when carrying out the update path.

Did you enjoy this article? If so, you may like the article How to remove Exchange from Active Directory. Don’t forget to follow us and share this article.



ALI TAJRAN is a passionate IT Architect, IT Consultant, and Microsoft Certified Trainer. He started Information Technology at a very young age, and his goal is to teach and inspire others. Read more »

This Post Has 6 Comments

  1. Hello ALI TAJRAN,
    I have theopposite issue. My exchange server’s .NET got upgraded to .NET 4.7.1 but Exchange 2013 CU is at 4 Build 847.32. This combination is also “not Supported”.
    The single step upgrade to CU19 would get to a “support configuration” is this even possible
    Then install CU23 then >NET 4.8?
    What would be your recommendation for upgrading to CU 23?

  2. Question, I am running CU 19, with Dot net 4.8+ , shouldn’t I be able to upgrade using CU 22 and CU 23? Without needing to downgrade then upgrade the dot netframework.

  3. Hi Ali,
    thanks for the sheet, but CU15 is no longer available. So what the steps should be, when updating a Server 2013 with CU smaller than CU15 ?


  4. Hi Ali,

    Thank you for taking the time and putting this together. I had issues with the Exchange installation and I did create a case with Microsoft. Stumbled upon your article and did the steps. What can I say? It worked perfect.

    For everyone here reading: Yes it will take a bit more time when following the flowchart as described by Ali, but it works!

    Again thank you a lot for the work that you put in for us all and sharing with us.

Leave a Reply

Your email address will not be published. Required fields are marked *

Back To Top