Bonjour Thomas
I'm not sure either to be available , who knows !
You don't need to be sure to pre-register and it is free !
The sooner you pre-register the more chance you have to be selected and it helps the organisation.
If you can't join, the only thing to do is to send a message on the website to postpone your participation.
As the 2019 edition wzs postponed, the organization has some incertitude on the number of particpants. There is a risk of a revenge attitude and massive demand.
Amicalement
Eric