One of our offices overseas wants to transfer their current old emails on to Office 365. They're currently on Exchange 2007. However, I was planning on transitioning them like I have done before to Exchange 2013. So my question is, if I built Exchange 2013 and got them ready to move on to the new Exchange then would that be pointless if they wanted to use Office 365? If they use 365, then would that mean the Exchange server I'm building for them will be too costly and pointless as it will instead use Exchange online?