Updated 22/6/2016 – .NET 4.6.1 is supported for Exchange Server 2016 CU2 and Exchange 2013 CU13 or later. For safe installation of .NET Framework 4.6.1 use the following steps:
- Update servers to at least Exchange 2016 CU2 or Exchange 2013 CU13
- For each server in turn, place server into maintenance mode:
- Install the new .NET Framework on the server
- Install the applicable hotfix:
- After successful verification and testing, take server out of maintenance mode.
As always, check the Exchange Supportability Matrix when determining which versions of .NET Framework to install or update on your servers.
Previous article text below:
The Microsoft Exchange team has issued a warning to customers to not install .NET Framework 4.6.1 on Exchange servers.
We wanted to post a quick note to call out that since yesterday, the .NET Framework 4.6.1 has been made a recommended update on WU (Windows Update).
We are working with the .NET team to ensure that Exchange customers have a smooth transition to .NET Framework 4.6.1, but in the meantime, delay this particular .NET update on your Exchange servers (information on how this can be accomplished can be found in the KB article 3133990, How to temporarily block the installation of the .NET Framework 4.6.1).
Be cautious when approving updates in your WSUS or other deployment system, that you do not inadvertently approve the update for your Exchange servers.
Update: If you need to remove the 4.6.1 update from your servers follow Jeff Guillet’s advice here.