Microsoft has been pushing its new Office icons across the board. They're now available for Office 365 customers on Windows, mobile, and the web. One area that hasn't received the new icon treatment is the Office Mobile suite for Windows 10.
While the UWP apps aren't receiving new features in the same way that we're seeing on iOS and Android, the MS Office Insiders Twitter account confirmed today that the apps will indeed get the new icons. No timing was provided, with Microsoft only saying that they're coming soon and more information will be shared when that happens.
Obviously, there aren't a lot of people still using the Office Mobile apps for Windows 10, which were originally made for phones and small tablets. They do have a future though, as Microsoft will likely continue to use them for devices that don't run Win32 apps, such as the Surface Hub 2 and the HoloLens 2. Both of those devices run Windows Core OS, something that we'll hear more about at Microsoft's Build 2019 developer conference in a few weeks.