The End of Life for Exchange server 2007 is April 11, 2017. While this doesn't mean that it will die on that date, there will be no more security updates, support from Microsoft, bug fixes, or time zone updates. Organizations still using Exchange 2007 should be working on a migration plan to Office 365 or Exchange 2016.
For more information on your options, see Exchange 2007 End of Life Roadmap (Microsoft)
As a reminder, Office 2007 is also no longer supported and as of October 31, 2017, it will not sync with Office 365 Exchange mailboxes (including Outlook.com). Users will need to upgrade to Office 2016 to continue syncing mailboxes, or switch to IMAP for email.