We reported about leak of WeChat UWP app in a screenshot sometime ago after some earlier reports of WeChat owners pausing work on a Windows 10 UWP app. Now it is almost confirmed as the WeChat UWP app is seen on a official Microsoft slide from Microsoft’s WinHEC presentation focusing on Windows Ink.
The app has been listed as an example app that will support Windows Ink photo annotations and Whiteboard feature. So, seems Microsoft is planning to bring Windows Ink to Mobile too, though more details about Pen support for Mobile is yet to emerge. We will let you know when we come to know more.