4.0.0-beta.0 (2026-09-19)
⚠ BREAKING CHANGES
- base-driver: ISessionHandler.createSession (@appium/types) and LegacyCreateSessionArgs — overload and type deleted, single-argument signature only.
- base-driver: BaseDriver.createSession and AppiumDriver.createSession — collapsed to the single-argument mplementation; capability validation now checks the one argument directly instead of scanning three positions for the first W3C-shaped value.
- base-driver: FakeDriver.createSession (and the base-driver e2e test double) — overrides updated to match.
- base-driver: RelaxedCapsPlugin.createSession — this plugin existed specifically to normalize capabilities across the (now-gone) three positions; its hook is simplified to a single caps argument.
- base-driver: POST /session wire route (w3c.ts) — payloadParams.optional no longer sends capabilities three times into the command args.
- the minimum supported Node.js engine is set to ^22.22.2 || ^24.15.0 || >=26.0.0