Upgrade to new wired version and use old hardware?

Hello: I have purchased and set up three of your Konnected wifi boards. They are working well. I want to purchase the new pro model as I need to expand the installation. My question: am I able to use the pro board as my main board and then expand that board using the old wifi boards? The old boards were expensive and I cant afford to just not use them and buy a bunch of pro boards.