Here's an article about it. https://www.torahmusings.com/2014/07/gelatin-halacha-recent-developments/
As noted, there has long been a big machlokes, though there were some big poskim who held that certain types of gelatin were kosher, even if made from treif animals, and many others of equivalent caliber who disagreed 100%.
Interesting, looks like none of the heterim were accepted mainstream. I would think there's an extremely small subset of people that are makpid on kashrus so far that they won't consume a supplement without a hechsher, but will be ok consuming supplements containing porcine gelatin because it has a kosher symbol, my question is, is
Ko catering to certain people or is
Ko deliberately misleading?
This week alone I found three people who were naively using Ko supplements because "it must be a good enough hechsher for supplements"