Used nappies should never be composted at home as the bacteria in human waste needs to be exposed to high temperatures to die. This can be solved in larger installations, but the regular composting facilities that handle food waste aren't equipped to handle nappies.
There is one facility that we work closely with in the US that composts our old version nappy after removing a few parts. A bit of information on how they work can be found at: https://earthbabyblog.wordpress.com/2019/02/13/turning-dirty-diapers-into-dirt-2/
Our nappies are today made out of ~55% bio/plant-based material, but this unfortunately doesn't mean that they can be composted.
As it was very difficult to compost the nappies, we have since launching our New Generation nappies 2018 moved our focus over from compostable materials to renewable materials. This to reduce the impact our nappies have on the greenhouse effect.