cannot change default language (DAWN THEME)

[moreforkidz]

Hello All , 

I'm working on finalizing our site using the Dawn Theme and want to have Dutch as default language for the site. 

But in the Edit Languages there is no option to change this see below 

So to solve this I wanted to edit the code like below (saw some info on this on Shopify.dev)

en.default.json -> change to en.json

and then 

nl.json -> change to nl.default.json

The locale "nl" already exists en A theme must have only one default locale file.

How can I solve this ? I can copy paste all translated stuff from the nl file but that means that English will not be available anymore.

thanks