Apple has previewed the overhauled user interfaces across the iPhone and other devices, known as Liquid Glass, at the WWDC2025 today.
Apple previews redesigned Liquid Glass user interfaces on iPhone, other devices
watchOS 26
If your Apple Watch runs watchOS 11, it should be compatible with watchOS 26
A claimed device compatibility list for watchOS 26 indicates that the upcoming update will support the same models as the current Apple Watch software.
watchOS 26 said to bring third-party widgets in the Control Center
watchOS 26 should support third-party widgets in the Control Center, allowing the Apple Watch to go beyond Apple's built-in toggles and tiles for the first time ever.