I have to report that when I fired up Lightroom Mobile on my iPad Pro, the much-hyped new interface was not present. It is still displaying the old interface. I also have an iPhone SE and the new interface is present on that.
Both devices are running version 10.1.1 of IOS and showing version 2.6.0 of Lightroom Mobile. I have deleted the Lightroom app on my iPad Pro and reinstalled it. It has made no difference.