How do you adjust the shoulder harness (move it up to a higher shoulder height opening as baby grows (not just adjust to be tighter)?
You need to open the flap on the backrest and tread the plastic parts through the holes from under the fabric. Then, retread the plastic parts through the lower or higher position to adjust to the shoulders of your child. I am attaching the right page from the manual HERE and also add an image.
Your -very berry- Eli.