The older sole is skywalk on the original boot, but they also do a lightweight sole that is more grippy. The skywalk is the sole for use on hard surface, & the other their off road sole.
I have never had an issue with the skywalk sole, & have never slipped while wearing them, but have done so while wearing lowa's. My son & i went to the factory on wednesday, & he got the peacekeepers. This boot was originaly made for running/tabbing in for the forces, & has a more flexible midsole than the defender or the field & fell(my favourite).
The peacekeeper is issued(in steel toecap version)to a number of police forces, so can be had via ebay if you don't mind steelys.
Rob