DidyKlick vs. DidyKlick 4u

The carrier is exactly the same, except for the waist belt.
DidyKlick 4u has a slightly curved waist belt.

didyklick 4u waistbelt
The new, ergonomically shaped waist belt moulds to your body, evenly distributing your child’s weight. An elastic strap ensures ideal positioning and secure fastening of the buckle. The waist strap webbing can be rolled up and secured in place with additional elastic straps. The width of the seat can be adjusted continuously using Velcro.

This means the baby carrier can grow seamlessly with your child from newborn sizing (8 lbs / 3.5 kg) through toddlerhood (45 lbs / 20 kg).