Microsoft released Office Mobile app April feature update for Build 17.8067. This update is available for both PC and Mobile and it is for Sow Ring Insiders .
The latest update brings Collaborative Editing & Open more files features for Excel and Insert recent links feature for PowerPoint, Excel and Word.
Changelog:
Collaborative Editing
Work with others at the same time in your workbook.
New in: 
Insert recent links
Easily attach hyperlinks to recent cloud-based files or websites, and create meaningful display names for people using screen readers.
New in: 
Open more files
You asked for it! You can now open files that contain ink.
New in:
