you use outlook for iOS or Android? Why you use it not?
Is there any security issues in outlook for iOS or Android because of the architecture from outlook?
It has its annoyances, like most software, but I use it. The architecture was changed long ago, it no longer uses AWS, so there are no concerns there. It's also compliant with the US government requirements now.
We find that Outlook for iOS is much better at working with Calendars than Apple's built in email/calendar app.
Outlook for Android works well for us.
We prefer to tell our users to use the Outlook versions for our mobile users.