macOS Sequoia (version 15) is the twenty-first release of macOS, shipped on September 16, 2024. iPhone Mirroring headlined: the phone's screen live on the desktop, controllable with the Mac's keyboard and trackpad, notifications included, while the handset stays locked in a pocket — the Continuity line's boldest merge yet. Window tiling finally arrived natively (drag-to-edge halves and quarters), Safari gained Highlights and a distraction-free Reader, and the Passwords app graduated credentials out of Settings.

Apple Intelligence rolled out from 15.1 on M-series Macs — writing tools, notification summaries, Genmoji and Image Playground following across the point releases — the Mac's share of the platform-wide AI staging.

iPhone Mirroring; window tiling; Apple Intelligence (15.1+, M-series); Passwords; Safari Highlights; video-call background replacement; Math Notes in Notes and Calculator; and hearing-health features flowing through paired AirPods.

iPhone Mirroring collapsed the last gap between Apple's two primary devices, and Sequoia's staged AI rollout matched the iOS 18 playbook — capabilities by hardware tier, features by point release. It closed the sequential numbering: its successor jumped to 26.