Centralized Mode (Combo Mode) Signature
Sigsync Office 365 Email Signature Software supports three signature deployment modes: Centralized Mode (Combo Mode), Server Mode, and Client Mode (Outlook Add-in). Centralized Mode (Combo Mode) is the recommended option because it combines both Server Mode and Client Mode, ensuring signatures are applied to all outgoing emails and also appear directly in the Outlook compose window.
After you register your Microsoft 365 tenant in Sigsync, the setup wizard automatically opens Centralized Mode (Combo Mode) and walks you through the configuration. The setup begins with Server Mode, which enables organization-wide server-side signature application. Once this stage is completed, you must select ‘Deploy Add-in’ in the Sigsync dashboard to deploy the Outlook Add-in and complete the Client Mode portion of the configuration.
Deployment of the add-in requires Office 365 Global Admin and Exchange Admin roles, as you will be redirected to the Microsoft 365 Admin Center (Integrated Apps) to finish the deployment.
Steps to Configure Centralized Mode (Combo Mode)
- From the Sigsync dashboard, go to ‘Manage Signatures’ > ‘Manage Tenants’ tabs.
- On the right-hand side, click ‘Details’ in the ‘Configuration’ column.
- Select ‘Centralized Mode’.
- Authenticate using an Office 365 Global Admin account on the Microsoft sign-in page.
- Select the senders to configure the Exchange online connectors.
- Deploy the Sigsync Signatures Outlook add-in.
Key Capabilities of Centralized Mode (Combo Mode)
- Compatible with all email clients and devices.
- Signatures are visible during email composition and editing.
- Option to enforce non-editable signatures, ensuring that signatures are automatically applied to all emails using server-side signature mode.
- Supports all major platforms - Windows, macOS, Linux, iOS, Android, and more.
- Ideal for organizations with users across multiple clients (e.g., Outlook, OWA, etc.)
- Administrators control how and when signatures are applied.
- Users can preview, switch to alternate signatures, or choose to configure server-side signatures
How Centralized Mode (Combo Mode) Works
Centralized Mode (Combo Mode) combines both Server Mode and Client Mode, giving your organization a unified and flexible email-signature solution.
It uses two signature mechanisms that work together:
- Server-side signatures – applied automatically in the cloud after the email is sent, ensuring consistent branding across all devices and email clients.
- Client-side signatures – inserted directly into the email body while composing in Outlook (Windows, Mac, and Outlook on the Web) using the Sigsync Signatures Outlook Add-in.
This approach ensures signature consistency on every device, while Outlook users also gain real-time visibility and the ability to manage signatures once the add-in is available.
Phase 1 — Configure Exchange Online Connectors
This is the initial setup step in Centralized Mode (Combo Mode). Once the connectors and rules are configured:
- Users can send emails from any device or client (Outlook, OWA, macOS, iOS/Android, Linux clients, etc.).
- Microsoft 365 evaluates the Sigsync transport rule and securely routes qualifying emails to Sigsync via the Outbound Connector.
- Sigsync processes each message and applies the appropriate signature based on Signature Rules and Azure AD attributes.
- The signed email returns to Microsoft 365 through the Inbound Connector and is delivered to the recipient.
This ensures signatures are applied consistently and immediately even before the Sigsync Signatures Outlook Add-in becomes available to all users, as Microsoft may take up to 48–72 hours for full propagation during Outlook Add-in deployment.
Phase 2 — Deploy the Sigsync Signature Add-in
Once the add-in is available to users:
- The appropriate signature is automatically inserted while composing an email.
- Users can manually select, switch, preview, or remove signatures from the add-in pane (based on permissions).
- Emails are sent directly through Microsoft 365 without routing through Sigsync servers.
- The recipient receives the email exactly as composed, including the selected signature.
This provides a smooth composing experience and full signature visibility in Outlook, while server-side signatures remain active as a fallback whenever the Outlook Add-in cannot be used.
Why is Centralized Mode (Combo Mode) Recommended?
Centralized Mode (Combo Mode) is recommended because it combines the strengths of both server-side and client-side signature methods, resulting in a more consistent, controlled, and flexible email-signature setup for the entire organization.
Key advantages include:
- Consistent results across all devices and email clients
Whether the user sends an email from Outlook, a mobile device, a browser, or a non-Outlook application, signatures are applied uniformly without requiring multiple configurations.
- Smooth operation during Outlook Add-in deployment
Since Microsoft may take 48–72 hours to fully propagate add-ins, server-side signatures ensure that emails continue to receive the correct branding during the deployment period.
- Reduced dependency on user actions
Even if users modify or skip their client-side signature while composing, server-side processing ensures the email still carries the proper signature when delivered.
- Centralized administrative control
All templates, rules, and branding elements can be managed from one place, eliminating the need to configure or troubleshoot individual user devices.
- Flexibility for Outlook users
Outlook users can view, switch, or choose signatures through the add-in, while all other platforms stay covered through server-side signatures.
- Automatic fallback mechanism
If the Outlook Add-in is unavailable or unsupported on a device, the server-side method applies the correct signature without any additional user action.
Centralized Mode (Combo Mode) offers a balanced approach that maintains consistency, ensures branding accuracy, and simplifies ongoing maintenance for administrators.
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