In addition, watch OS 9 allows users to pin their favourite apps for quick access
Redesign of notifications has been completed. And the Siri UI has been reworked and simplified.
It is compatible with Apple Watch Series 4 or later, iPhone 8 or later, and iPhone SE (second generation) or later, running iOS 16 or later.
With the exception of 2021, Apple typically releases their new software with a new watch model.