i think i saw something saying that gen 1,2,3,5 and maybe 6 got new shiny colors but the others hadn't gotten them yet
Some shiny Pokemon have been recoloured- this will be an ongoing process
All 1st, 2nd, 3rd & 6th gen Pokemon- i found it, it was in the game file listed as readme, so i am assuming they just havent gotten to gen 4 yet.