First off...last years skis are not "old school"...Ar5s would be old school, but I understand your thought.
Secondly, last years Alpha 2 are the same as this years Halos, while this years Alphas are the same as last years Alpha 1s. Main differences are the base, core, and flex. The Alpha 1/Alpha has a sintered race base, lighter core, and is a bit stiffer. The Alpha 2/Halo has a more durable/lower maintenance base, a slightly heavier core, and is a little softer.
Think of it this way AR6/AR7 = Alpha 2/Halo, Pipe Cleaner = Alpha 1/Alpha.