Office 365 works best with the latest version of Office, Office 2013, Office 2010, Office 2016 for Mac, and Office 2011 for Mac. Office 365 works with slightly limited functionality with Office 2007. If you have an earlier edition of Office, you will need to update to a newer version of Office in order to use Office 365; or you can subscribe to one of the many Office 365 plans that include the latest version of Office. In addition to getting the latest version of Office as part of your subscription, you will also get automatic updates, so your Office will always be up to date.
Know more about Office 365: Office 365