Specs aren't out on it yet, but evidently Royal Enfield has increased the engine size on the Himalayan, and introduced water cooling, to give that bike more power. More compression, higher RPM limit, different gearing. Faster top speed, more torque. Geometry looks a bit improved, too.
"Itchy Boots" got an opportunity to ride a prototype. Official specs aren't going to be published until November 7th, but she vlogged her test ride in India and was glowing about it. She put tens of thousands of rough miles on a first gen Himalayan.
https://www.youtube.com/watch?v=XKibLgw6JJ4I'm really impressed with the Android maps integration on the instrument panel. Bluetooth sync the phone to the bike and your maps just show up on the display if you program a route. No more mounting the phone to the handlebars. The Africa Twin has this. My Aprilia sort of has it, but it required a $200 add-on and it uses Aprilia proprietary software and maps rather than Google Maps. Good part is the maps are available offline, bad part is you have to go out of your way to update them.
ETA: I also looked up the altitude of the town she began her ride from in northern India, Leh. She began her ride at over 11,000 ft. And was still pleased and could tell the new Himalayan had more punch than her old model. One of the passes she took hits 18,000 ft. New model really lives up to its name.