Updates for Skype for Business Server 2019 (KB4470124) (original) (raw)

This article specifies the applicability of Microsoft Skype for Business Server 2019 updates for each server role.

Note: Skype for Business Server 2019, August 2025 update includes critical security updates for the Skype meetings application. Starting October 15, 2025, the Skype meetings application may experience functionality issues if this hotfix is not installed.

Important:

  1. Install the required hotfix updates.
  2. Run the PowerShell script on your Skype for Business Server Front End (FE) machine.

Get the updates that are released for Skype for Business Server 2019

Installation methods

Prerequisites

To apply this update, you must have Microsoft .NET Framework 4.5.2 (Offline Installer or Web Installer) installed.

Install the update

The Server Update Installer applies all updates for the appropriate server role in one operation.

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

Download Download the August 2025 Server Update Installer

Note: Updates for Skype for Business Server 2019 will no longer be auto-installed by Microsoft Update. You must manually download SkypeServerUpdateInstaller.exe from Microsoft Update, and then use the following installation steps.

To apply the update to the Front End servers in a pool

  1. Type the following cmdlet: Get-CsPoolFabricState -PoolFqdn If this cmdlet reveals any missing replicas, run the following cmdlet to recover the pool before you apply any updates: Reset-CsPoolRegistrarState -ResetType QuorumLossRecovery.
  2. On the first server that you want to update, run the following cmdlet: Invoke-CsComputerFailOver -ComputerName This cmdlet moves all services to other Front End servers in the pool, and takes this server offline.
  3. Install the required additional Windows features.
    Add-WindowsFeature RSAT-ADDS, Web-Server, Web-Static-Content, Web-Default-Doc, Web-Http-Errors, Web-Asp-Net, Web-Net-Ext, Web-ISAPI-Ext, Web-ISAPI-Filter, Web-Http-Logging, Web-Log-Libraries, Web-Request-Monitor, Web-Http-Tracing, Web-Basic-Auth, Web-Windows-Auth, Web-Client-Auth, Web-Filtering, Web-Stat-Compression, Web-Dyn-Compression, NET-WCF-HTTP-Activation45, Web-Asp-Net45, Web-Mgmt-Tools, Web-Scripting-Tools, Web-Mgmt-Compat, Windows-Identity-Foundation, Server-Media-Foundation, Telnet-Client, BITS, ManagementOData, Web-Mgmt-Console, Web-Metabase, Web-Lgcy-Mgmt-Console, Web-Lgcy-Scripting, Web-WMI, Web-Scripting-Tools, Web-Mgmt-Service
  4. Run the Server Update Installer, and then select Install Updates to upgrade the server role.
    You can also run the following parameters together with the SkypeServerUpdateInstaller.exe command:
    • The /silentmode switch applies all applicable updates in the background.
    • The /silentmode /forcereboot switch applies all applicable updates in the background, and then automatically restarts the server at the end of the installation process, if it is necessary.
    • The /extractall switch extracts the updates from the installer, and saves the updates in a subfolder that is named "Extracted" in the folder in which you ran the command.
  5. Run BootStrapper.exe.
  6. On the upgraded server, run the following cmdlet: Invoke-CsComputerFailBack -ComputerName The server is returned to service.
  7. Repeat steps 2–6 for every server that has to be upgraded.

To apply the update to a Back End server or Standard Edition server

  1. Log on to the server that you are upgrading as a member of the CsAdministrator role.
  2. Start the Skype for Business Server Management Shell: Select Start, select All Programs, select Skype for Business 2019, and then select Skype for Business Server Management Shell.
  3. Stop Skype for Business Server services. At the command prompt, type the following command: Stop-CsWindowsService.
  4. Stop the World Wide Web service. At the command prompt, type the following: net stop w3svc.
  5. Close all Skype for Business Server Management Shell windows.
  6. Run the Server Update Installer, and then select Install Updates to upgrade the server role.
    You can also run the following parameters together with the SkypeServerUpdateInstaller.exe command:
    • The /silentmode switch applies all applicable updates in the background.
    • The /silentmode /forcereboot switch applies all applicable updates in the background, and then automatically restarts the server at the end of the installation process if it is necessary.
    • The /extractall switch extracts the updates from the installer, and saves the updates in a subfolder that is named "Extracted" in the folder in which you ran the command.
  7. Start the Skype for Business Server Management Shell: Select Start, select All Programs, select Skype for Business 2019, and then select Skype for Business Server Management Shell.
  8. Start Skype for Business Server services. At the command prompt, type: Start-CsWindowsService.
  9. Restart the World Wide Web service. At the command prompt, type: net start w3svc.
  10. Apply the changes to the SQL Server databases by doing one of the following.
    Note: When you run the Install-CsDatabase cmdlet, you receive an error message that you can safely ignore. The error message in the request is expected if you are updating the database on a computer that isn't hosting the Central Management Store.
  1. If the Skype for Business Back End pool uses the SQL AlwaysOn availability group, update the AlwaysOn databases as follows:
  2. Install the update on your Skype for Business server or servers.
  3. Run the following PowerShell command in your Skype for Business Management Shell (logged in by using an account that's appropriately permissioned to apply changes to the SQL AlwaysOn databases), as follows:
    Install-CsDatabase -Update -ConfiguredDatabases -SqlServerFqdn [sqlpool.contoso.com] -Verbose
    Note: In this command, replace [sqlpool.contoso.com] with the fully qualified domain name (FQDN) of your AlwaysOn availability group.

Uninstallation methods

Uninstall the update

Remove the update from an Enterprise Edition pool that has two front-end servers

To do this, follow these steps:

  1. Stop new connections to other front-end servers by running the following command on both front-end servers: Stop-CsWindowsService -ComputerName <Computer.FQDN>.
  2. Uninstall any updates.
  3. Restart the server, and make sure that both front-end servers are accepting new connections.
  4. After both front-end servers are updated, you must run the following command: Reset-CsPoolRegistrarState -ResetType FullReset Then, run the following command: Start-CsPool -PoolFqdn <Pool.FQDN>.

Remove the update from an Enterprise Edition pool that has at least three front-end servers

To do this, follow these steps:

  1. Obtain the list of the upgrade domains for the Enterprise Edition pool that is associated with a front-end server. To do this, run the Get-CsPoolUpgradeReadinessState cmdlet on the front-end server.
  2. Uninstall any updates for each upgrade domain.
    Notes:
    • You must uninstall updates from one upgrade domain at a time.
    • You can remove updates in parallel from all servers that are in the same upgrade domain.
      To uninstall all servers that are in the same upgrade domain, follow these steps:
    1. Run the following command: Invoke-CsComputerFailover -ComputerName <Computer.FQDN>.
    2. Uninstall updates on front-end servers that are associated with an upgrade domain.
    3. Run the following command: Invoke-CsComputerFailback -ComputerName <Computer.FQDN>.
      Note: You must repeat step 2 to uninstall updates from every upgrade domain until all upgrade domains in the pool are updated.

You must do several configuration operations, depending on the kind of Skype for Business 2019 Enterprise Edition back-end servers that you are using.

Note: If database mirroring is enabled for the back-end databases, we strongly recommend that you use the Invoke-CsDatabaseFailover -NewPrincipal Primary command, and then run the Get-CsDatabaseMirrorState -PoolFqdn cmdlet to verify that the primary server is principal for all databases before you run the Install-CsDatabase cmdlet. If Persistent Chat is co-located (that is, the Persistent Chat front-end service and back-end database are running on the same server), you must run the Install-CsDatabase cmdlet together with the ExcludeCollocatedStores parameter.

Skype for Business Server 2019 Monitoring Databases

If Skype for Business Monitoring databases are deployed on standalone SQL databases, run the following command:

`Install-CsDatabase -ConfiguredDatabases -SqlServerFqdn <FEBE.FQDN> -Verbose

`

In this command, <_FEBE.FQDN_> is a placeholder for the actual value.

Skype for Business Server 2019 Standard Edition and other roles

  1. Uninstall updates on the Standard Edition or any other server role.
  2. Restart the server after you uninstall these updates, if it is necessary.

Known issues in this update

List of server roles and the updates that apply to them

Skype for Business Server 2019 - Standard Edition server

Skype for Business Server 2019 - Enterprise Edition - Front End server and Back End server

Skype for Business Server 2019 - Edge server

Skype for Business Server 2019 - standalone Mediation server

Skype for Business Server 2019 - Director server

Skype for Business Server 2019 - Persistent Chat Front End server

Skype for Business Server 2019 - Administration Tools

Skype for Business Server 2019 - Video Interop server

References

Learn about the terminology that Microsoft uses to describe software updates.