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This cumulative update resolves a list of issues in Microsoft Lync Server 2013, Mediation Server. The version number of this update is 5.0.8308.992.

Issue that the cumulative update resolves

This cumulative update fixes the issue in which PSTN call is dropped when it's put on hold by a PSTN callee in Lync Server 2013.

This cumulative update also fixes the issues that are described in the following previously released articles:

How to install the update

This cumulative update improves the reliability, stability, and performance of Microsoft Lync Server 2013 Mediation Server. To install the cumulative update, use one of the following methods:

Method 1: Cumulative Server Update Installer

The Cumulative Server Update Installer applies all updates for the appropriate server role in one operation. To use the Cumulative Server Update Installer, follow these steps:

Note If User Account Control (UAC) is turned on, you must start the Cumulative Server Update Installer by using elevated permissions to make sure that all updates are installed correctly.

  1. Download the Cumulative Server Update Installer.

  2. Run the Cumulative Server Update Installer by using the user interface (UI) or by using a command line.

    Note When you click Install Updates, the UI indicates which updates are installed.

    To run the Cumulative Server Update Installer, run the following command: LyncServerUpdateInstaller.exe Note The following text describes parameters that you can use together with the LyncServerUpdateInstaller.exe command:

    • The /silentmode switch applies all applicable updates in the background.

    • The /silentmode /forcereboot switch applies all applicable updates in the background. Additionally, the switch automatically restarts the server at the end of the installation process if this is necessary.

    • The /extractall switch extracts the updates from the installer and saves the updates in a subfolder that's named "Extracted." The subfolder is in the folder in which you ran the command.

After you run the Cumulative Server Update Installer, you must update all the applicable back-end servers. Check out how to update the back-end servers.

Method 2: Microsoft Update

The update is also available from the Microsoft Update website.

Note After you install this update by using Microsoft Update, you must update the databases on the back-end servers. Check out how to update the databases on the back-end servers.


There are no prerequisites for installing this cumulative update.

Registry information

To use one of the cumulative updates in this package, you do not have to make any changes to the registry.

Restart requirement

You may have to restart the computer after you apply this cumulative update.

Update replacement information

This cumulative update replaces the April 2016 cumulative update 5.0.8308.956 for Microsoft Lync Server 2013 Mediation Server.

Update package installation information

To apply this cumulative update, run MediationServer.msp on computers that are running the following server role:

  • Lync Server 2013 - Mediation Server

Removal information

To remove this cumulative update, use the Add or Remove Programs item in Control Panel.

When you install the update, insert the source CD or provide the path where the source files can be found if you are prompted.

The global version of this cumulative update uses a Microsoft Windows Installer package to install the cumulative update. The dates and the times for these files are listed in Coordinated Universal Time (UTC) in the following table. When you view the file information, the date is converted to local time. To find the difference between UTC and local time, use the Time Zone tab in the Date and Time item in Control Panel.

After the update is installed, the global version of this update has the file attributes, or a later version of the file attributes, that are listed in the following table:

File name


File version


File size


Date (UTC)


Time (UTC)



See the general information about the standard terminology that Microsoft uses to describe software updates.

Get the latest cumulative update for Lync Server 2013.

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