The revision could be as straightforward as making a larger hole in the case and using a 3.mm jack. Or it could be as complicated as a board and/or case redesign if the revision cannot be accommodated by the current board and/or case.
The rest of the industry seemingly has no issue with using a 3.5mm jack for a 12V trigger. Arylic which I understand to be their parent company uses 3.5mm 12V trigger jacks.
IMHO if they included an adapter then it would defeat the purpose of having a 2.5mm jack. Someone will just plug the jack into the unit and then plug their headphones into the jack.
