New release v4.25.0

Critical update for Exchange Online and Benefactor Circle users. New signature marking, short variable names, and improved Graph API resilience.

2025-12-22

Benefactor Circle add-on users with mailboxes in Exchange Online should update to this version as soon as possible. Microsoft will begin changing roaming signature HTML processing shortly. Update as soon as possible to avoid potential negative impact on the parameters DeleteScriptCreatedSignaturesWithoutTemplate and DeleteUserCreatedSignatures.

🔗Streamlined signature design with shorter variables

Designing signatures with limited space just got easier. We have introduced shorter replacement variable names that can be used interchangeably with the original long names. This applies to both default and custom variables.

  • CurrentUser can now be shortened to U (e.g., $UVariableX$)
  • CurrentUserManager can now be shortened to UM (e.g., $UMVariableX$)
  • CurrentMailbox can now be shortened to M (e.g., $MVariableX$)
  • CurrentMailboxManager can now be shortened to MM (e.g., $MMVariableX$)

🔗Enhanced diagnostic warnings and resilience

Set-OutlookSignatures now provides improved proactive warnings to identify potential misconfigurations or environment constraints:

  • GPO Overrides: The script will warn you if a Group Policy Object setting takes precedence over registry values set by the script, such as DisableRoamingSignatures.
  • Graph API Resilience: We have made Graph API queries more robust by implementing automatic retries after five seconds to compensate for brief network or data center "hiccups".
  • Template Auditing: Receive warnings for non-standard image formats (outside of JPG, PNG, and GIF) or signatures exceeding 30,000 characters, which may fail in Outlook add-in launch events.

🔗Updates for Benefactor Circle add-on users

The Benefactor Circle add-on and Outlook add-in receive several key enhancements for advanced deployments:

  • Automatic Image Embedding: Images are now embedded when setting Outlook for the web signatures (classic and roaming) regardless of global parameters, ensuring high-quality display even for default signatures.
  • Improved Cleanup Logic: The DeleteScriptCreatedSignaturesWithoutTemplate parameter is now more aggressive in removing "leftover" signatures when toggling roaming signature settings.
  • Admin Tooling: The Entra app creation script has been updated to force the use of the PowerShell Gallery and ensure all required package providers are present.

🔗Detailed changelog

For a comprehensive list of all changes, dependencies, and fixes, please consult the official changelog.

🔗Turn every small email moment into a professional advantage

Email signatures and out-of-office replies may seem minor, but think about how often people see them.

We help organizations centrally manage and standardize these touchpoints across all users — unified Outlook branding everywhere, with zero external data exposure. No manual effort, no inconsistencies, no data leaving your environment. With Set-OutlookSignatures, every email becomes a consistent, secure, and fully controlled brand experience.

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