Our instances received October update last weekend (we are crm4), nov on version 9.1. However, the new interface has not been enabled.
I have asked Microsoft why is that and it was explained to me, that the new interface is only for the new trials at the moment. If you want to enable it for your existing instances, it requires manual activation by MS people. So if you need, you can try to contact them and get the new update already.
I was also told, that this updated interface will be rolled out to existing customer later as an opt-in feature.