You know, when the English dub gets around to Serena's haircut I have a gut feeling they will be stupid and leave the opening titles as they are. If they don't update the titles, the young viewers would confuse Serena's new look as an entirely new character or something.
My god her short hair doesn't suit that outfit. I guess your post in the XY060 review thread about "Serena's new short hair won't suit some of her outfits" was right. But still, it's cool Fennekin will be evolving into Braixen in a coming episode.