Not all Office functionality may be available, and you may encounter stability problems where apps unexpectedly quit.
You are advised to update to 15.35 or later, but even that’s no guarantee. Microsoft says that versions 15.34 and earlier are not supported, and you may not be able to launch the apps.
It also notes that users of Office 2016 for Mac may experience problems with High Sierra … Word, Excel, PowerPoint, Outlook and Lync have not been tested on macOS 10.13 High Sierra, and no formal support for this configuration will be provided. It doesn’t go as far as to say the software will not work, but hints at this. The default name will be Macintosh HD.Microsoft has announced in a support document that Office for Mac 2011 will not be supported under macOS 10.13 High Sierra.
To uninstall Microsoft Office 2008, do the following: Step 1: Quit all applications
The version of Microsoft Office that you download and install from Microsoft 365 will not replace any existing versions of Microsoft Office on your computer. The Technology Support Center recommends that you uninstall your existing version of Microsoft Office before installing the latest version to avoid technical issues that may arise from having more than one version installed.