Bevy 0.17 → 0.18 — Migration cheat sheet

Released 2026-01-13. Apply top-down — earlier items break later builds if skipped.

When to use this skill

• Compiler errors after a bevy = "0.17" → bevy = "0.18" bump.
• LLM emits 0.17-era API names from training data.
• Auditing a PR for hidden 0.18-incompatible patterns.
• Hot-fixing a downstream crate that hasn't shipped 0.18 yet.

The renames you'll hit first

Observers: Trigger<E> → On<E>

// 0.18 (also 0.17)
fn on_hit(on: On<Damage>) { let _e = on.event(); }