According to this review (which I completely agree with, regarding sound), there is no physical difference.
https://marco.org/2016/03/02/beoplay-h6-v2-review
"It looks nearly identical to the first H6 — the only apparent differences are the driver cover cloth, which has gone from green to black (in the black model), and the barrels on the headphone cable, which no longer have metal finishes (but now fit through slightly thinner openings in many phone cases).
The H6 remains one of the most comfortable headphones I’ve ever worn, with a very lightweight design and excellent earpads. Isolation of outside noise (and leakage of music to the outside world) remains average for closed headphones, and portability is excellent for over-ear wired headphones.
Upon any physical inspection between the first and second H6, you’ll think nothing has changed."