Apple expands on-device AI in iOS 18.4 with private generative suggestions for Mail and Notes

AI · 4 min read

Apple's iOS 18.4, released to developers this week, expands the platform's on-device generative AI capabilities, enabling Mail and Notes to offer draft generation and summarisation that never leaves the iPhone. The models are smaller, optimized for the Neural Engine, and designed to run locally for common composition tasks.

For designers this changes the interaction model: suggestions appear as context-aware cards inline, with a new API for controlling suggestion strength, tone presets, and undo behaviour. Apple also introduced new accessibility variables so assistants can adapt suggestions to reading level and assistive modes.

Developers can opt in using a revised Privacy-Preserving Suggestions API that returns tokens and confidence scores rather than raw model outputs, letting apps build transparent UI flows. Early tests show latency under 150ms on A17-class devices, making these features viable for real-time workflows.