The Borealis V2 still fits on the QNT or Sprint NT(narrow track) trike from Inspired Cycle Engineering in Britain. The primary difference from the V1 is that the top is 5mm lower than the V1. This reduces the frontal area a bit and improves visibility for the rider. In addition to the lower top the mirror bumps are smaller also helping with visibilty. This is made possible by using a smaller higher quality mirror than on the V1.
Here's a picture showing the difference in height of the V1 and V2.