Since Azure File Sync which is currently on GA you can upgrade your old agents in your Azure or On-Premise servers. It’s also very easy to do that and can be done by following few steps which I will show you.
Go to the Windows server 2016 or Windows Server 2012 R2 where you have earlier installed the agents. The path will be as follows.
Please click on the AFSUpdater.exe
In the next step you can see this message
Please click on the update button.
Once it’s updated you will find the below screen
Now you need to restart the server. Once the server come back you find the following screen.
Please note that there is no changes required from Azure Side of it. For more details on how to configure Azure File Sync you can read my old post here.