See below Exclaimer's compatibility with a range of different servers, plans and email clients:
Plans
Microsoft 365 Plans
- Microsoft 365 Business Basic
- Microsoft 365 Business Standard
- Microsoft 365 Business Premium
- Microsoft 365 E3
- Microsoft 365 E5
- Microsoft 365 F3
- Microsoft 365 GCC
- Microsoft 365 F3
- Office 365 A1
- Office 365 A3
- Office 365 A5
- Office 365 E1
- Office 365 E3
- Office 365 E5
- Office 365 F3
Google Workspace Plans
- Business Starter
- Business Standard
- Business Plus
- Enterprise
Directories
Microsoft 365
- Microsoft Azure AD
Exchange On-Premises
- Microsoft Azure AD (Works with a free Azure AD tenant)
Google Workspace
- Google Directory
Server-Side Signatures
Mail Server Support (Microsoft 365)
- Microsoft 365 (Exchange Online)
Mail Server Support (Exchange On-Premises)
- Exchange 2016 CU18 and above
- Exchange 2019 CU1 and above
Mail Server Support (Google Workspace)
- Google Workspace
Mail Client Support
- All Standard mail clients supported
Client-Side Signatures
Exclaimer Signature Update Agent (Microsoft 365 and Exchange On-Premises)
Windows
- Microsoft .NET framework 4.6.2 (x86 and x64)
- Windows 8 or above:
- Microsoft Outlook 2016 or above
- Microsoft Outlook 2016 or above
Exclaimer Outlook Add-in (Microsoft 365)
Users whose mailboxes exist in Exchange Online
Mailbox type:
Microsoft 365 mailboxes only
Windows
- Outlook on Windows (Microsoft 365 Subscription) [version 2409 (Build 18025.20000)]
- Outlook on Windows (Retail Perpetual) [version 2501 (Build 18429.20132)]
- Outlook 2024 on Windows (Volume-licensed perpetual) [version 2408 (Build 17932.20222)]
- Microsoft Outlook Web Access
- Microsoft Windows 10, Windows Server 2016 or above
Mac
- Outlook on Mac [version 16.89 (24090815) or above]
NOTE: Only the New Outlook interface is supported. Go to Outlook > New Outlook to enable it.
Mobile devices
- Android: Outlook version 4.2433.0 or above
- iOS: Outlook version 4.2433.0 or above
Microsoft 365 Plan
Your Microsoft 365 plan must allow access to deploy Microsoft 365 Apps through Microsoft AppSource. Certain plans, such as Office 365 E2 do not support this.
We recommend: Use an Outlook version that supports Nested App Authentication by June 2025.
Exclaimer Outlook Add-in (Microsoft 365)
| 17th Feb 2025 |
Legacy tokens turned off for all tenants. Admins can re-enable legacy tokens via PowerShell. |
| June 2025 | Legacy tokens turned off for all tenants. Admins can no longer re-enable legacy tokens via PowerShell. Contact Microsoft for any exceptions. |
| Oct 2025 | Legacy tokens turned off for all tenants. Exceptions are no longer allowed. |
Gmail Signatures (Google Workspace)
- Gmail (web browser)
Exclaimer portal Web Browser Support
- Google Chrome 17.x (preferred browser)
- Internet Explorer 9 or above
- Mozilla Firefox 10.x+
- Apple Safari 5 (Mac)
- Microsoft Edge
- Opera
WARNING! Exclaimer does not support the following:
Microsoft 365 Plans:
- Microsoft 365 Personal
- Microsoft 365 Family
- Microsoft 365 Apps
- Microsoft 365 GCC High
- Microsoft 365 DOD
- Microsoft 365 Apps for enterprise
- Microsoft 365 A1
- Microsoft 365 F1
- Enterprise Mobility + Security E3
- Enterprise Mobility + Security E5
Google Workspace Plans:
- G Suite Basic
NOTE: You'll need to complete the onboarding and configuration process for Exclaimer and, as part of this, provide credentials for a Microsoft 365 Global Administrator account or a Google Workspace Super Admin account, depending on the email service you use.
We recommend: Use an Outlook version that supports Nested App Authentication by June 2025.
Exclaimer Outlook Add-in (Microsoft 365)
| 17th Feb 2025 |
Legacy tokens turned off for all tenants. Admins can re-enable legacy tokens via PowerShell. |
| June 2025 | Legacy tokens turned off for all tenants. Admins can no longer re-enable legacy tokens via PowerShell. Contact Microsoft for any exceptions. |
| Oct 2025 | Legacy tokens turned off for all tenants. Exceptions are no longer allowed. |