What I am interested in is if one of the following: tailcap from M21-X Warrior, remote pressure switch RM20 or RM22 will fit and work on newer lights like M2X and M3X?
In theory they should work but I would like if someone that has both of this models (M21 and M2X or M3X) could check threads compatibility.
Thanks
Maybe Mitko could give you an answer in a few days 
I also thought he is the right man to ask but did not want to bother him.
Let’s hope he sees this thread 