We're just a day away from the end of support of Windows 10 Mobile, and this time it will be dead for good. In a new support document, Microsoft also announced the end of life date for the Office apps on the mobile OS, and those won't be supported after January 12, 2021.
Throughout the following year, Microsoft will be shipping bug fixes, security fixes, and technical support for issues, and that's it. Don't expect to see any new features during this time.
The apps in question here are the Office UWP apps. The wording of the blog post is a bit ambiguous, in fact, as it's not exactly clear if the apps themselves are being killed off, or if they just won't be supported on Microsoft's unsupported mobile OS. The document says, "On that date, app users will no longer receive security updates, non-security hotfixes, free assisted support options or online technical content updates from Microsoft."
Microsoft's Office UWP apps were never very widely available outside of phones, and being that operating systems like Windows 10X will support containerized Win32 apps, they don't really have a place elsewhere anymore. Naturally, we've reached out to Microsoft for clarification on this matter.