Question: what is the difference between ultraboost and ultraboost 20?
Answer: While I couldn't see or feel the difference (my Ultraboost 19s have 100+ miles on them and may be riding lower than when they were new), the Ultraboost 20 measures 7mm closer to the ground in both the forefoot and heel. It features the same 10mm drop as the Ultraboost 19 but has less Boost.