We ware looking to migrate from a zimbra server at a hosting provider to our own server, with zimbra Version 8.0.7.

The problem is we don't know the version of the zimbra server at the hosting provider, wich version will be able to sync with each other? Is it possible to setup our new server as ' secundairy' mailserver so all mail wil be sent to both servers? and if this is possible, will existing mail also be sent to the new server?