With the release of Office 2016 in September 2015 a small drawback is introduced for Exchange 2007. It won’t work anymore.
If you try to connect, you’ll will get a message: “The resource that you are trying to use is located on an unsupported version of Microsoft Exchange. Contact your e-mail administrator for assistance.”
As stated in the Exchange Server Supportability Matrix
Outlook 2016 is not supported by Exchange 2007.