If not, you will not be able to use the EWS feature, as Outlook try to connects for the port 443, more information in the next Bugs: Important note: EWS only works if you have the Proxy role installed and properly configured. To configure Outlook 2016 with EWS for Zimbra Collaboration need the next: Outlook 2016 supports now 100% Office 365, and only works with Exchange 2010 or above.The look and feel is the same like Ofice 2013 for Windows, or almost the same.
Microsoft will release Office 2016 soon, this new Office have interesting new features: This is certified documentation and is protected for editing by Zimbra Employees & Moderators only.
