What’s changed is that 1.8 is a major release with new functionality that in all probability demands more from your hardware.
And Brian warned us about this at the beginning of the Roon journey:
Another thing to keep in mind: Roon is not static. It will receive software updates over time, and as always, we’re going to continue pushing the functionality forward as hardware improves. Buying something that’s just barely sufficient today is a recipe for a sub-par experience in a year. Likewise, the hardware we’ll be recommending six months from now (April 10, 2015) will be six months better than what we’re recommending today.