Surface finish is 4000 grit matte vs the current one's 1500 grit polished.
Like the Fringe/Manic pair I suspect they just wanted new colors to draw new buyers. With All the Tropical Heats being 1500 grit polished, the new one;s 4000 gt surface separates it from the others, much like the 900Global's Hook series (one pearl is 4000 grit matte, while the other pearl, the hybrid and the solid are all 2000 grit polished).
"None are so blind as those who will not see."