Earlier this year, Microsoft introduced the new Outlook.com, which helps you focus on what matters, collaborate effortlessly, and get more done. The new Outlook.com delivers an exciting set of email and calendar experiences across all your devices. The majority of Outlook.com email accounts have upgraded to the new service. Outlook.com email accounts with shared calendars will begin receiving this upgrade in September 2016.
During the final stages of the upgrade process, shared calendars may be temporarily placed in “read only” mode. Read only mode will stay in effect until all email accounts sharing the calendars have been upgraded. Notifications when new events are created, edited, or deleted in shared calendars may also be disabled during the upgrade process. All other Outlook.com mail and calendar features will continue to work normally and you will continue to have uninterrupted access to your email.
For more information about the new Outlook.com features, go to Get help with Outlook.com.