Microsoft has warned users of Office for Mac 2011 not to upgrade to Apple's macOS High Sierra when the new operating system launches next month.
"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," Microsoft wrote in a support document.
In the same document, Microsoft told those running the newer Office 2016 for Mac that they must update its applications to version 15.35 or later, if they intend to upgrade their Macs to High Sierra. (Version 15.35 was released in June; since then, Microsoft has issued 15.36 in July and 15.37 in August.) "In some cases, you may not be able to launch the Office apps [of version 15.34 under High Sierra]," Microsoft said.