https://arstechnica.com/gadgets/2018/09/microsoft-suspends-development-of-touch-friendly-office-apps-for-windows/

Microsoft has stopped developing new features for the touch-friendly Office Mobile apps for Windows 10, reports the Verge.

Word Mobile, Excel Mobile, and PowerPoint Mobile first made their debut with Windows 8.1. Their significance is twofold: they have a user interface that's designed to be touch-friendly, and they're built using Microsoft's modern UWP (Universal Windows Platform) framework. They've been regularly updated since their introduction, but no longer. The use of UWP meant that the same app core could be used on both desktop Windows and Windows 10 Mobile, but with Windows 10 Mobile no longer a going concern, this compatibility is no longer a priority.