Because it is a Microsoft app that I am using. I am not the only person with this problem.
The problem of not being able to download the current version of the app from the Google Play Store?
Microsoft fixed this issue two months ago!! Microsoft added an option to allow you to select the way that links are handled, and screenshots were posted here proving that at the beginning of November (though I believe the update may have been available for
a week or two already at that point).
Microsoft doesn't run the Google Play Store, Google does. If Google won't let you download the current version of the app, from servers that are owned and run by Google, go ask Google for support!!!!