That'd be my guess, but I don't really know. They just left the "utf8" type as broken 3-byte gibbled UTF-8, and added the "utf8mb4" type and "utf8mb4_unicode_ci" collation for "no, actually, I want UTF-8 for real".
It won't. We settled on using stateful combining characters instead.
(Remember when the selling point of switching the world to Unicode was "represent all writing systems with a single stateless 16 bit encoding"? Yeah, well, lol.)