Yep, we are talking a total new unit here.
The new “Di” designated models require a different transducer and internal circuitry in the units as well as software. If it were just a transducer and software upgrade than you would be able to do so but the difference in internal circuitry nixes the deal here.

I wish they would have given these Di units different model names as it would have cut down on the confusion (mine especially)!