skip to Main Content

Update .NET Framework in Exchange Server

We like to update .NET Framework in Exchange Server 2013/2016/2019 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 asked a lot.

A lot of Exchange admins have seen Exchange Servers breaking and not working after a Cumulative Update. This article will teach you how to update .NET Framework when updating Cumulative Updates in Exchange Server.

Introduction

It’s important to know that .NET Framework is a must for Exchange Server. When installing Cumulative Updates on Exchange 2013/2016/2019, 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 up to date and on the latest supported CU. Microsoft makes no claim that an upgrade failure will not occur using this method, which may result in the need to contact Microsoft Support Services.

Keep .NET Framework and Exchange Server up to date

Keep your Exchange Server 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.

How to update .NET Framework and Exchange Server Cumulative Update

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 CU 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 for:

  • Exchange Server 2013
  • Exchange Server 2016
  • Exchange Server 2019

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.

Exchange Server 2013

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.

Update .NET Framework in Exchange Server 2013

The Exchange 2013 upgrade compatibility path will be:

  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
Update .NET Framework in Exchange Server 2013 example

Exchange Server 2016

Let’s have an example with the following company called EXOIP. The company is currently running Exchange Server 2016 CU3 and .NET Framework 4.6.1. They want to update to the latest Exchange Server version, which is Exchange Server 2016 CU21. Let’s have a look at how to do that without breaking the Exchange Server.

Update .NET Framework in Exchange Server 2016

The Exchange 2016 upgrade compatibility path will be:

  1. Upgrade to Exchange 2016 CU4
  2. Upgrade .NET Framework to 4.6.2
  3. Upgrade to Exchange 2016 CU9
  4. Upgrade .NET Framework to 4.7.1
  5. Upgrade to Exchange 2016 CU12
  6. Upgrade .NET Framework to 4.7.2
  7. Upgrade to Exchange 2016 CU14
  8. Upgrade .NET Framework to 4.8
  9. Upgrade to Exchange 2016 CU21
Update .NET Framework in Exchange Server 2016 example

Exchange Server 2019

Let’s have an example with the following company called EXOIP. The company is currently running Exchange Server 2019 CU1 and .NET Framework 4.7.2. They want to update to the latest Exchange Server version, which is Exchange Server 2019 CU8. Let’s have a look at how to do that without breaking the Exchange Server.

Update .NET Framework in Exchange Server 2019

The Exchange 2019 upgrade compatibility path will be:

  1. Upgrade to Exchange 2019 CU3
  2. Upgrade .NET Framework to 4.8
  3. Upgrade to Exchange 2019 CU10
Update .NET Framework in Exchange Server 2019 example

Articles that you may be interested in:

Conclusion

In this article, you learned how to update .NET Framework in Exchange Server. Save the Cumulative Updates when available for download, as Microsoft will delete them after a newer version comes out. You might need it when carrying out the update path.

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!

Did you enjoy this article? If so, you may like the article Install Exchange Server 2016 step by step with GUI. Don’t forget to follow us and share this article.

ALI TAJRAN

ALI TAJRAN

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 18 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 Exchange 2013 CU19, with Dot net 4.8+ , shouldn’t I be able to upgrade using Exchange 2013 CU22 and CU23? Without needing to downgrade then upgrade the dot netframework.

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

    thx
    Bruno

  4. I had a lot of issues throwing when updating Exchange CU. After following this approach, it worked perfect.

    You saved my ass. Thanks Ali.

  5. 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.

  6. The only page that got me up to date with my Exchange Servers. So many errors with updating and nobody had a clue but this made it work. I owe you a lot. Thanks for all your articles it’s the best page ever.

  7. This article was great. Thank you very much. I tried patching CU6 to CU19 and had .Net Failures. Rolled back the servers and took your approach and it went perfectly. Took a long time but no issues!

    1. hi Howard – I also need to upgrade from CU6. In Ali’s chart, he suggests we’d need to update to CU9 before then updating .NET. Where did you get the iso for CU9 from?

        1. hi Ali
          I really appreciate your reply. I did see that in the article, but to be honest I was a little wary of it. I assume you’ve downloaded from there with no issues?

  8. This upgrade path is simply not correct. You can perfectly upgrade directly from for instance .Net 4.7.1 and Exchange 16 CU11 to .Net 4.8 and CU18. First put your server in maintenance mode, install .Net 4.8, reboot and than upgrade to Exchange 2016 CU18. No intermediate upgrade to CU14 is needed. After the upgrade to CU18 reboot again and bring your server back in production mode. That’s it.

    1. Sometimes there is no right and wrong, just like in this case. What I have shown is the PREFERRED method. It’s possible to upgrade immediately to the latest CU version. But, as I said in the article, it’s NOT the recommended way of doing.

      The Exchange team discussed the following. See the last line in particular:

      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 up to date and on the latest supported CU. Microsoft makes no claim that an upgrade failure will not occur using this method, which may result in the need to contact Microsoft Support Services.

      In your case, the Exchange CU upgrade went successfully, and that’s fine. If you do get errors or problems after upgrading Exchange Server to the latest CU in one jump, try to think about this article.

Leave a Reply

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