Hi Marco,
You know where I am from and located.
Laminar Research is not in the market of developing aircraft. As said previously in other postings their objective is developing XP software and not add-on aircraft.
If the aircraft you have a particular interest in was supplied with XP10 and you are seeking to have it within XP11 then try loading the relevant file into Plane Maker and save the file as a XP11 aircraft. I understand this will work. I have also seen when starting X-Plane and selecting aircraft there is a "check box" that allows older version aircraft to be installed and or recognised..
If and when XP12 is released your aircraft may make the list. Otherwise your only option at this stage is to go with 3rd party add-on from an independent supplier/provider.
Glenn