developer preview configuration update

My O2 Lumia 720 received an update an hour ago ?? No idea what it was for but after the usual update procedure it reported developer preview configuration update successful

The phone was displaying Denim previously but now displays Cyan, although I have Denim features... confused am I

Anyone care to shed light on what the update achieved apart from displaying Cyan in the about setting

I got this same thing on my 930. No changes that I have seen though. I'm on denim.