When deploying self-developed Excel add-ins via the Office 365 administrator method, I encountered an issue where the latest version of the code could not be automatically updated.

Question

I created the Excel add-in project using the official Office add-in development toolkit for Visual Studio Code and deployed the add-in via the administrator method. However, after updating the code for the second time, the Office 365 client did not automatically update to the second version of the code.

Attempts made:

Closing and reopening all Excel files on the client side – no effect.

Waiting overnight before reopening the client – no effect.

Updating the version number in the .xml file – no effect.

Deleting and redeploying the add-in – no effect.

Ultimately, the second version of the code was successfully loaded only after checking "Disable cache" in the Network tab of the attached debugger on each client and reloading.

Is it possible for the client to automatically refresh to the new code after the administrator updates the add-in? It seemed to work previously, but recently it has not been functioning correctly.

Answer 1

When deploying Excel add-ins via the Office 365 administrator method, the client may not automatically refresh to the new code after an update due to caching issues. Here are some important points to consider:

1. Caching: Office applications often cache add-in manifests and resources to improve performance. This can lead to situations where updates are not reflected immediately. Clearing the Office cache can help ensure that the latest version of your add-in is being used. You can follow the instructions to Clear the Office cache.
2. Version Number: It's crucial to update the version number in the manifest file each time you make changes. This signals to the Office client that a new version is available. If the version number is not updated, the client may not recognize that an update has occurred.
3. Admin Consent: If the add-in is deployed within an organization, some changes may require admin consent before they are applied to users. Ensure that any necessary permissions or consent have been granted for the updated version.
4. Sideloading: If you are testing changes, consider sideloading the add-in to see if the updates reflect correctly. This can help isolate whether the issue is with the deployment method or the add-in itself.
5. Network Tab Debugging: As you discovered, disabling the cache in the debugger can force the client to load the latest version. This is a useful troubleshooting step but should not be necessary for regular updates.

In summary, while the client should ideally refresh to the new code automatically after an update, caching issues can interfere with this process. Regularly clearing the cache and ensuring the version number is updated are key practices to facilitate smoother updates.

Answer 2

This is a known issue, and it's typically a caching quirk, not a deployment failure. When you deploy an Office add-in via the admin center, Office clients are quite zealous about caching the add-in's resources. While updating the version in the manifest dictates deployment, it doesn't compel the client to refresh the web assets, such as JavaScript and HTML. That's why disabling the cache in the debugger instantly reveals the new code.

For production environments, the best practice is to implement cache busting on the web side.

For instance, you could modify the script or resource URLs by appending a version query string, or by employing hashed file names. This approach ensures that when the administrator updates the add-in, the client is compelled to fetch the updated files.

Unfortunately, there's no surefire method to compel all Office clients to automatically refresh cached add-in code following an admin update. While clearing the Office cache or restarting the application can provide some relief, the most effective long-term solution involves implementing cache control on the hosted assets.

Answer 3

Hi Joan He

Thank you for reaching out to the Microsoft Q&A Forum. 

Based on your description, I understand that after updating your centrally deployed Excel add-in through the Microsoft 365 admin center, the updated code is only loaded after disabling the cache in the debugger and reloading the add-in. 

You may want to review Anderson’s response above and try the suggestion shared there to see if it can help in your case. 

I’ve reviewed the available Microsoft documentation and related community discussions. Unfortunately, there is currently no official documentation or supported method that ensures Office clients will automatically refresh cached add-in code immediately after an admin update. This behavior may be related to how Office applications cache add-in resources, and updates may not always be picked up automatically.

I understand this may not be the answer you were hoping for, and I appreciate your understanding. Please feel free to let me know if you have any other questions. 

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