We’re currently working on a Microsoft Word add-in in my day job. The company already has an Outlook add-in and wanted to use the same manifest file for the Word add-in. The manifest files have some keys that look similar. Although much of the content appears similar, merging them is not possible.

There are three types of Office add-ins: Task pane, Content, and Mail. These have different schema definitions at the top of the file. Consequently, it’s not possible to combine these three different types of Office add-ins. If an add-in needs mail permissions, it cannot work in Word, and if it requires document permissions, it cannot work in Outlook.