I don’t think you understand. 4o introduces a new multimodal Sky replacing the old one. They have only released clips of the new voices. It’s never been in the iOS app. The one you refer to is the old voice model. If you listen to the linked video above it’s very obviously not the same voice (I use Sky on iOS btw)
To be honest the new sky is obnoxious and overly emotive. I’m not trying to flirt with my phone.