Update 3/17/13 - Added information about additional update steps from KB2809243.
Just like previous versions of OCS/Lync, there are two methods to update the servers with OCS/Lync cumulative updates. You can use Microsoft Update/WSUS or you can use LyncServerUpdateInstaller.exe. Both ways accomplish the same thing, but what I find is that a lot of customers who use the Microsoft Update/WSUS method forget to then go back and apply any database updates that are needed. This blog post focuses on the LyncServerUpdateInstaller.exe method, as I prefer using it over the Microsoft Update/WSUS method:
Installing Standard Edition Server Cumulative Updates
To apply the latest cumulative updates to a Standard Edition Server, all you need to do is run LyncServerUpdateInstaller.exe and click on Install Updates:
The installer will detect what Lync services have been installed on the server and will display whether or not the latest update has been applied. Once the updates have been installed, restart the server if prompted to do so and then skip down to the "Installing Lync Database Updates" at the bottom of this article.
Installing Enterprise Edition Pool Front End Server Cumulative Updates
With the release of the Lync Server 2013 Cumulative Updates, the process for updating Front End Servers in an Enterprise Edition Pool has changed slightly. Most of the changes have to do with the move to using Windows Fabric to replicate data between the Front End Servers in an Enterprise Edition Pool. With the introduction of Windows Fabric a couple of other concepts were also introduced, User Groups and Upgrade Domains. Both are created and managed by Windows Fabric automatically. You can read more about these new features in the Lync Server 2013: Windows Fabric & User Groups blog post. Because of these new concepts in Lync Server 2013, you will need to update your Front End Servers one at a time, making sure that services are fully restored on that server before you move on to the next Front End Server in the pool in order to make sure that you maintain quorum and at least one copy of all of the user groups. The flow chart below, from the Upgrade or Update Front End Servers TechNet article, walks through the process:
Running Get-CsPoolUpgradeReadinessState should return something similar to the following output:
If the cmdlet returns True for IsReadyForUpgrade for the server you are going to update, you can then run LyncServerUpdateInstaller.exe and apply the necessary updates on the Front End Server:
This process is the same as updating a Standard Edition Server. Once the updates have been installed, restart the server if prompted to do so. Once the server has been restarted, make sure that all of the services have returned to the running state and then run the Get-CsPoolUpgradeReadinessState cmdlet again and repeat the process until all of the Front End Servers in the pool have been updated. You can then skip to the "Installing Lync Database Updates" at the bottom of this article.
Installing Lync Database Updates
Also like previous version of OCS/Lync there Lync database updates that need to be applied. The steps are detailed in the "Step 2: Apply the back end database updates" section in KB2809243. You apply the update by running the following PowerShell cmdlet on one Front End Server in each Enterprise Edition Pool and all Standard Edition Servers in your environment:
Install-CsDatabase -ConfiguredDatabases -SqlServerFqdn FEBE.FQDN -Verbose
Additional Update Steps
Also make sure that you follow the steps in sections "Step 3: Enable the Mobility service" and "Step 4: Enable the Unified Communications Web API" in KB2809243.
Installing Updates on Other Lync Server 2013 Servers
To apply the latest cumulative updates on other Lync Server 2013 servers in your environment, just run LyncServerUpdateInstaller.exe and click on Install Updates.