Yes, v2.1 of HOTT is now available. Currently just from Amazon.
In terms of changes it apparently formalises the Warband/Shooter movement swap, adds an optional base-width movement measurement system and includes lots of new army lists. It's also in a larger print, A4 format, so those of us feeling the ravages of age may find that more to their tastes.
So, on the whole, it's probably worth getting only if you're a completist (my copy is on order) or don't currently have a copy.