Note: The Microsoft Add-in will enable support for the Outlook mobile app.
As an admin, you can install the Office add-ins to users in your organization through the Centralized Deployment feature available in the Microsoft 365 admin center. Centralized Deployment is the recommended and most feature-rich way for most admins to deploy add-ins to users and groups within an organization.
To install an add-in in the admin center, follow these steps:
In the admin center, go to Settings > Integrated apps > Add-ins page. If you don't see this option, go to the Settings > Add-ins page instead.
2. Click Deploy Add-in at the top of the page and then click Next.
3. Click Upload custom apps.
4. Download manifest.xml from https://gitlab.com/new_old_stamp/office-addins/-/blob/main/public/manifest.xml?ref_type=heads, choose this file in the next step and select Upload.
5. On the next page, select Everyone, Specific users/groups, or Just me to specify who the add-in should be deployed to. Use the Search box to find specific users or groups.
If you install the add-in yourself, you can select Change who has access to the add-in later to install it for more users.
Note: Only users with installed Add-in will have signatures applied to emails after deployment.
6. A green tick will appear once the add-in is deployed.
Note: Microsoft 365 can take up to 48 hours to process Outlook add-ins, and you may need to relaunch the Outlook app.
The required version:
Platform | Outlook version | Supported version and later |
Windows | - Microsoft 365 subscription | from Version 2104, build 13929.20296 or above |
Mac | - new UI | from Outlook |
Web browser | - Modern Outlook UI when connected to Exchange Online: | - |
Note: If you have an Office 2021 LTSC or any other oldest Office with an old Outlook version, please update them to the newest version specified above.
Also, you can check the Microsoft article Outlook JavaScript API requirement sets for more details.