Microsoft offers many different email/account domains such as outlook.com, hotmail.com, live.com, msn.com, Microsoft Exchange, Office 365, etc. Not all accounts in these domain are migrated to use the REST API. Accounts that have been migrated can be linked with CaseFox and once linked Calendar events created in these accounts will be synced with respective online calendars in these Microsoft accounts. Also, emails sent from your clients to your clients will be sent via these accounts. An event created by CaseFox in these calendars, if updated outside of CaseFox, is automatically updated in CaseFox.
By the way, CaseFox also integrates with many Google services such as Drive, Calendar, Tasks, and Email. CaseFox also integrates with Dropbox, Box, Xero, QuickBooks, LawPay, etc.