Managing a new Exchange Server 2016 EAC having your mailbox on a previous version

During the transition between Exchange Server 2010/2013 to Exchange Server 2016, before moving the mailboxes any administrator that tries to access the EAC will be redirected to the legacy system.

Solution

In order to be able to manage it, the solution is simple, we just need to work on the URL, using the following example:

https://<server>/ECP/?ExchClientVer=15.1

The result is shown in the image below.