no, pdf versions are not just magic numbers.
hi yackel
each version has its specific characteristics and might have some specific constraints.
for the X versions, i'm pretty sure that you need to use the color management.
you can see this as a task to check (just activate it) or as a step that makes sure that the pdf has the quality you're aiming to.
ciao
a.l.e
(the color management gets activated in the document setup...)