Kyrotech salvage question

Out of curiosity I was doing some research on kyrotech salvage and when it was first added to the game. As the biggest bottleneck for many if not all players I wanted to know more about around when it became a necessity for new toons to clear gear 8. Apparently it came out back around 2019 according to some sources but that didn't seem right to me. If galaxy of heroes celebrated its 5th or 6th anniversary this January (can't remember right now) that would mean that the salvage had been in the game for almost 5 years. As many of the older toons in the game never required this salvage until gear 12 finishers I'm confused as to when this gear was actually implemented into completing lower level gear levels for newer toons.