I recently received this updated version of the Allston, and am an even bigger fan than I was of the first edition Allston.
The two main updates over the previous version are; revised rear retention system and a fixed position under the ear chin strap.
The previous double Velcro retention system, that I do not feel helped securely snug the rear of the helmet to your head is now a 'BOA' style dial that is fixed to the inner liner and helps snug in the rear of the helmet quite nicely.
The previously adjustable straps under the ear, that I feel are a constant battle to find the right position as well as lay flat on the face; have been replaced with a non adjustable, sewn strap that is very comfortable next to skin and is a vast important in my eyes.
The stand out feature of this helmet above all other previous Bern models would certainly be it's ventilation; with 16 large vents, I have no issues wearing this with or without a cycling cap on warmer days. This is my go-to helmet for commuting around town, running to the store/bar, and any other cycling adventure where I would prefer a more durable helmet over a super lightweight one.