August 2025 update for Skype for Business Server

Introduction

Microsoft continues to actively support Skype for Business Server, particularly its Subscription Edition (SE), with regular patch releases. The August 2025 hotfix provides several important stability, security, and compatibility improvements, while also paving the way for future product developments.

Supported Versions

The August 2025 hotfix applies to the following versions :

Skype for Business Server 2015 CU13 (build 6.0.9319.881) — KB3061064
Skype for Business Server 2019 CU8 (build 7.0.2046.553) — KB4470124
Skype for Business Server Subscription Edition (SE) RTM (build 7.0.2046.820) — KB5065372

These builds are the minimum versions required to take advantage of the new dedicated hybrid app feature.

Key new features and recommendations

Dedicated hybrid application

Until now, Skype for Business used a Microsoft-managed Shared Service Principal for authentication and access to Exchange Online (archives, presence via calendar, profile picture synchronization).
Microsoft now strongly recommends — and will soon require — the implementation of a dedicated hybrid application managed by each organization via their Entra ID tenant. Failure to do so will result in the discontinuation of hybrid functionality.

Continuity of Skype Meetings Application

If this fix is not applied before October 15, 2025, the online meetings module may no longer function correctly. Administrators should therefore act quickly.

PowerShell script to run

For Skype for Business Server 2015, it is imperative to run the add_sfbassets.ps1 script after installing the patch to ensure continued functionality of the Skype Meetings Application.
For the Subscription Edition, Microsoft also provides the ConfigureSkypeforBusinessHybridApplication.ps1 script to run on the Front End server to configure the dedicated hybrid application.

Recommended action plan for administrators

Hotfixes are available via the Microsoft Download Center and can be installed manually or using standard administrative tools. It is recommended to:

Back up your environment before any update
Retrieve the appropriate hotfixes based on your role (Core, Front End, Edge, Web Components, Enterprise Web App)
Use the Server Update Installer with elevated rights (UAC disabled or run as administrator)
Run the script (SFB 2015: add_sfbassets.ps1 or SFB SE: ConfigureSkypeforBusinessHybridApplication.ps1)
Restart services after installation to ensure the hotfixes are taken into account

Why this update is crucial ?

Enhanced security : The dedicated hybrid application improves control, traceability, and authentication security between on-premises environments and Exchange Online.
Maintains hybrid functionality : Without this installation, critical features, such as archiving and presence, may cease to function.
Meeting continuity : Ensuring the functionality of Skype Meetings Application beyond October 15th is essential to avoid major disruptions within the organization.

Conclusion

The August 2025 hotfix update for Skype for Business Server is much more than a simple security fix : it represents a transformation of the hybrid architecture, replacing a shared service model with a more secure and controlled dedicated model. Administrators have a crucial window of opportunity to act : apply updates according to the version, run the provided scripts, and ensure that hybrid and meeting features remain functional after October 15, 2025.

A well-planned transition will preserve the user experience while strengthening the infrastructure’s security posture.