If you still can, I'd advise returning the old one and have them provide you with the new updated 1715 in it's place - it sounds like you paid for it, so you should have it.
The previous 1715's are fine, so it will work well & you'll enjoy it - there are many owners who are using it and enjoying them quite a bit.
However, there are significant differences in power gains with the "max" performance program in the new unit, and there are now 3 different performance programs instead of 1 in the older unit, including an 87 octane tune and 2 different premium gas programs.
Best of luck!