- Microsoft 365 apps update without using Windows Update, they use the Office Content Delivery Network (CDN) and check this using a scheduled task. - The task compares the version of Microsoft 365 Apps on the computer to the version of Microsoft 365 Apps on the update location. If there's a difference between the two versions, the update process determines which files are different and need to be updated on the local computer. - Only the files that are different are copied down to a Download folder on the local computer, and they're downloaded in a compressed form. - The scheduled task then attempts to install the updates in the background, without requiring any user intervention. - Updates can't be applied if the Office program that has to be updated is being used by the user. If this is the case, the task tries to apply the updates the next time that the scheduled task runs. If updates can't be applied for several days, [users see a message](https://learn.microsoft.com/en-us/microsoft-365-apps/updates/end-user-update-notifications-microsoft-365-apps) that updates are ready to install. If the user restarts the computer and updates haven't been applied, the updates are applied as Windows starts. - A [deadline](https://learn.microsoft.com/en-us/microsoft-365-apps/updates/configure-update-settings-microsoft-365-apps) can be configured to enforce the installation of available updates. - You can view all Microsoft 365 app installation current versions per-tenant at [this link](https://config.office.com/officeSettings/inventory). # Sources - [Overview of the update process for Microsoft 365 Apps - Microsoft 365 Apps | Microsoft Learn](https://learn.microsoft.com/en-us/microsoft-365-apps/updates/overview-update-process-microsoft-365-apps) - [Configure update settings for Microsoft 365 Apps - Microsoft 365 Apps | Microsoft Learn](https://learn.microsoft.com/en-us/microsoft-365-apps/updates/configure-update-settings-microsoft-365-apps) - [TIL: You can see all of your Office versions in config.office.com and update them to the latest Monthly Enterprise channel to help with CVE-2023-23397. : sysadmin (reddit.com)](https://old.reddit.com/r/sysadmin/comments/11tgus5/til_you_can_see_all_of_your_office_versions_in/) - https://youtu.be/qHDFffWHdKk - https://youtu.be/g1rDR2aOAQc