Primorac is a popular, cheap blade. Bringing out a newer more expensive model is clever from Butterfly
I was being a bit naughty there, obviously. Hopefully it isn't more expensive, but Butterfly have a bad track record of releasing similar blades and asking more for them.
I can understand wanting to refresh the designs. They introduced their new logo recently and probably want it on their whole range. It also keeps them slightly ahead of the counterfeiters, who now have to come up with a new copy design of their own.
Also, I wonder if the new design is only for the Made in Japan Primorac?