I am developing an Office Add-in using Office.js. This new extension will be a re-implementation of an old COM Office extension. The problem I am facing right now is how to install the extension for my customers. According to the documentation, there are four ways to deploy the manifest.xml: the Office Add-in Store, Microsoft 365 upload, SharePoint Add-in library, and a shared network folder added to trusted sources. None of these deployment solutions works for my case.
My customers are organizations that use volume-licensed Office 2019 and Office 2021 (which rules out Microsoft 365 and SharePoint), and they are in a closed network without internet access (which rules out the Office Add-in Store). There are approximately 50 PCs in each organization, which makes going individually through each PC and adding the network-shared folder with the manifest.xml to trusted sources impractical.
My plan is to create simple web server separately within each organization and (somehow) distribute the custom manifest.xml file for each organization. The manifest will contain a Taskpane with a URL pointed to the organization's web server hosting taskpane.html (with its business logic). I have prepared my manifest.xml file, which I tested locally using office-addin-debugging and office-addin-manifest.
In previous COM Office extensions, there was a way to create an MSI installation package that would update the appropriate registry keys and automatically load the extension when the user opened Word, Excel, etc. Is there a way to replicate such an installation process and sideload the manifest.xml with a web extension to Office 2019 (2021)?
