Straight from the source, Microsoft’s Office 365 API docs here
The Office 365 APIs are REST services that provide access to Office 365 data, such as: mail, calendars, and contacts from Exchange Online; files and folders from SharePoint Online and OneDrive for Business; users and groups from Azure Active Directory.
I must say, I’ve used my UNT Exchange mailbox under Apple’s native Mail app up to now but really prefer this one… especially for mail fetching time. It seems like Apple’s Mail takes much too long for just checking mail… almost like it’s syncing all folders or unnecessarily updating related notifications… This app is much more responsive.
Microsoft released a new app for iOS and Android yesterday to help you manage your inbox. Outlook, the massively popular email client for the desktop, now has an official home on Android and iOS.
Apple appears to like the app, as they have featured it on the landing page under ‘Best New Apps’ which has helped the app climb the charts in the store. Currently, the app is sitting in the 15th position in the ‘Top Free’ chart and has been climbing rapidly over the past 12 hours or so.