Office 365 is hosted by Microsoft in the cloud.
It can be accessed via the web or from mobile devices, using Internet Explorer, Firefox, Chrome or Safari browsers. Office 365 is not dependent on the operating system that is being used.
Office 365 will no longer support Internet Explorer 8 after 8th April 2014.
For the best, richest experience with Office 365, we strongly recommend that you upgrade to the latest version of Internet Explorer, Internet Explorer 11. Modern versions of Internet Explorer offer faster web browsing, integrated spell-checking, improved security, and more. Internet Explorer 8 users will not be blocked from connecting to Office 365 after 8 April 2014; however, Internet Explorer 8 users should expect slower performance with Office 365’s Outlook Web App and other Office Web Apps.