1.there are 2kind of Peugeot307/Citroen flip key on market. one is 0523(before 2005), one is 0536(after 2005) . when the flip key rolled, you can get the Number 0523/0536 the side of the flip key blade . on the plastic print 0523 or 0536. if you have the Peugeot/Citroen tool (PPS2000) ,you can update the 0523system to 0536 system. that means the 0536 key works well on 0523 car.
2. after 2005 all the Peugeot/Citroen all use 0536 flip key(2button and 3button) ,all 0536 key all works well on both Citroren and Peugeot Car.