We just made the decision to purchase 2 new licenses of Exchange Enterprise Edition. Our existing organization is Exchange 2013, and we are using Office365 for our clients, which are Outlook 2016. Our licensing would allow for us to have 3 Exchange Standard servers and 2 Enterprise Edition servers. Has anyone done an upgrade to Exchange 2016 from 2013 who could speak to the pluses and minuses of doing the upgrade? I welcome any feedback from either the technical or the managerial side of things. Considerations include downtime, redundancy (The switch to Enterprise was triggered by the 1TB limitation on dag-enabled databases, and we need two EE servers to make the biggest databases redundant). At the moment, any single server can carry the whole organization, so I can do an upgrade with minimal disruption... But I'd like to know from someone who has done this what to expect... Any advice?