You should be able to sell Ukdah to Unfallen but you can't trade systems with Vodyani because they use Arks instead of colonies.

PARAdoxiBLE wrote:

You should be able to sell Ukdah to Unfallen but you can't trade systems with Vodyani because they use Arks instead of colonies.

Thanks for your answer PARAdoxiBLE ! That's what I could have read concerning Vodyanis, but unfortunately the option didn't displayed with the Unfallen :/

Do you know in which section of the diplomacy board this option shoud appear please ? Couldn't find a screenshot or video precisely with that.

Thanks !

Right there. Star systems.

Though the xml code does not specify Unfallen as excluded, maybe they can also be unable to trade outpost since they create roots and instantly colonize a system, skipping the outpost stage.

Good idea for the xml; I'm gonna to make a little test quickly with an other race and make an answer here; bad point for Lumaris if so, though. 

Thanks for your quick feedback

Ok, now I can confirm that's not possible to sell outposts to Unfallen too :

I hope I'm only unlucky to meet first the uncompatible factions and this isn't unbalanced for the Lumaris; could you please tell me which xml is it ? I'd like to add incompatibilties with this faction while solving my problem.

Thanks a lot !

You cannot sell outposts to Unfallen or Vodyani because of their unique colonization mechanics. Neither of them create outposts to grow into colonies. While it is probably possible to add this ability in the xml files, it would likely cause a host of other issues.