Just take a close look at that logo with the glass rainbow on it. WWDC 2025 is going to be all about glassy UIs and iOS 19.
Apple Will Give iOS 19 and iPadOS 19 a Big UI Overhaul with Use of Glass-like Elements, as Hinted by the new WWDC 2025 Logo
iOS 19 and iPadOS 19 are rumored to feature a big UI overhaul and will use a lot of glass-like elements. If you needed a hint if that is definitely going to be the case, then just have a look at the new WWDC 2025 logo/graphic Apple posted.

Though this change does look exciting, but once you start to realize how much burden this is going to be on older iPhone and iPads with slower GPUs, I’m not sure if it’s going to be a great idea.
This reminds me of the time when iPhone 6 Plus was a disaster to use with too many dropped frames, all thanks to its 1080p display. I really hope it doesn’t happen again.