Using classic Outlook for Windows in business environments
For an Outlook add-in update, the behavior depends on what was changed.
- If only the web app files changed, such as HTML, CSS, or JavaScript, users should get the update automatically. Ribbon artifacts such as icons can be cached, so closing and reopening Outlook may be required. If the old UI still appears, clearing the Office cache can force Outlook to download the latest artifacts again.
- If the manifest was changed, the add-in package must be updated and the manifest version must be increased. Without raising the manifest version, Outlook won’t recognize the update correctly.
- If the add-in was deployed by an admin, some manifest changes require admin consent again before users receive the updated version.
For a ribbon update, check these items in order:
- Confirm whether the ribbon change was made in the manifest.
- Ribbon command changes are part of the add-in package/manifest, not just the web app.
- Increase the manifest version.
- Any manifest change requires the version number to be raised.
- Redeploy the updated add-in package.
- If the add-in was published through organizational deployment or Marketplace, the updated package must be deployed again.
- Check whether the manifest change requires admin consent.
- Admin consent is required again if the update changed:
- requested permissions
- scopes
- events
- Until consent is granted, users can remain on the old version or be blocked from the add-in.
- Admin consent is required again if the update changed:
- Restart Outlook.
- Cached add-in artifacts may delay what appears in the ribbon.
- If it still does not update, clear the Office cache.
- This removes cached add-in artifacts and forces Outlook to download them again the next time Office starts.
If the symptom is specifically that Outlook shows an upgrade message, this indicates the add-in is still upgrading and the current item should be closed and reopened after a short wait.