I have iPad MM172LL/A, OS version 11.12 (15B202). I would like to install Microsoft One Note. When I got to app store on the iPad and search for Microsoft One Note, it's not showing up. What's going on?
What’s going on is your iPad doesn’t meet the minimum version, so the listing is likely suppressed. It also could be a country region restriction, but that’s harder for others to test for you. The simple reason is you didn’t purchase an older version of the app to re-download that and/or the developer removed the old version entirely.