Released: August 2025 Skype for Business Server Hotfix Updates

Summary 

Microsoft has released Hotfix Updates (HUs) for Skype for Business (SfB) Server that introduces support for a new security-related feature. Starting with the August 2025 Hotfix (HF), Skype for Business Server has the capability to configure a Dedicated Hybrid Application to ensure secure and reliable hybrid integration with Exchange Online. 

Additionally, this release includes updates for the Skype Meetings Application. After October 15, 2025, the Skype Meetings Application may not function correctly unless this Hotfix is installed. 

Note: For Skype for Business Server 2015, administrators must also run the add_sfbassets.ps1 script after installing the update to ensure continued functionality of the Skype Meetings Application. The script is available on the SfB 2015 Download Center Page. 

Supported Versions 

Hotfix Updates are available for the following versions: 

• Skype for Business Server 2015 CU13 (KB3061064) 

• Skype for Business Server 2019 CU8 (KB4470124) 

• Skype for Business Server Subscription Edition (SE) RTM (KB5065372) 

What’s Changing? 

Previously, Skype for Business Server utilized a Microsoft-managed Shared Service Principal for authentication and access to Exchange Online in support of hybrid features, including: 

• Archiving to Exchange Online 

• Calendar-based presence 

• Profile picture synchronization 

With this release, organizations can (and should) configure a customer-managed Dedicated Hybrid Application within their Microsoft Entra ID tenant. Failure to implement this configuration will result in the discontinuation of hybrid features as outlined in Plan to integrate Skype for Business and Exchange. 

From the following server versions onward, Skype for Business provides support for the Dedicated Hybrid Application: 

Details regarding the prerequisites and steps required to set up the Dedicated Hybrid Application for Skype for Business are available in the Configure dedicated hybrid application in Skype for Business Server documentation. 

 
The Skype for Business Server Team