Note
Office Add-ins that use the unified manifest for Microsoft 365 are directly supported in Office on the web, in new Outlook on Windows (preview), and in Office on Windows connected to a Microsoft 365 subscription, Version 2304 (Build 16320.00000) or later.
When the app package that contains the unified manifest is deployed in AppSource or the Microsoft 365 Admin Center then, if the manifest has a valid "alternateIcons" property, an XML manifest is generated from the unified manifest and stored. This XML manifest enables the add-in to be installed on platforms that don't directly support the unified manifest, including Office on Mac, Office on mobile, subscription versions of Office on Windows earlier than 2304 (Build 16320.00000), and perpetual versions of Office on Windows.