The version being sold, at a discounter price, is the RC2 (Release Candidate 2) and fully compatible with X-Plane 11.30 RC1.
This means you will have to have, at least, the 11.30 RC1 version of X-Plane since the AW139 does not play well with the stable 11.26 version.
Head out to X-Rotors' official website for more information and to grab this version.