Hello Claes, you were right, icc profiles v4 are not supported (yet) by argyll.
I found this recent discussion on the argyll mailinglist:
https://www.freelists.org/post/argyllcms/ICC-v4-Support-Roadmapped,1
There Graeme Gill, the maker of Argyll, says:
At this point possibility of adding ICC V4 support depends on the
successful conclusion of a commercial licensing deal involving
ArgyllCMS, the negotiations of which have been going on for
some time. If that agreement were to go ahead, then ICC V4
support would be about 12 months or so away. If that deal fails to eventuate, then there is no current road map, although many of the small updates in the past have taken it in the direction of making the task easier.