Migration guide

Upgrading from v3 to v4 and from v2 to v3.

v3 → v4

Rust: the port I/O functions in commands are now async (they run on Tauri's blocking pool instead of the main thread, so a read waiting for data no longer freezes the UI). Add .await: commands::open(app, serial, …).await?. MSRV is now 1.90.
JS package: exports now has separate import/require entries with their own types (index.d.cts); the development condition pointing at guest-js/*.ts and the guest-js sources in the npm tarball are gone.
read() now reads bytes and decodes them in JS with the port's encoding and a streaming decoder (UTF-8 characters split across reads are kept). It no longer calls the native read command.
watch() no longer uses the port's read timeout (1 s by default) as its batch window. Without timeout / serialDataFlushIntervalMs data is delivered within ~20 ms and as soon as size bytes are buffered.
CMUX is now real 3GPP 27.010 basic mode (0xF9 framing, SABM/UA, CLD); before, the frames were not understood by modems. openMuxChannel(dlci) accepts 1–63.
Android: the plugin no longer offers the app for every USB device (the old device_filter.xml had a catch-all entry); it matches the supported chips plus any CDC-ACM device.
Rust commands::open takes two more optional arguments at the end: dtr, rts (pass None, None for the old behaviour).
Android: USB Ethernet / RNDIS devices are no longer listed as serial ports; FTDI ports open with a 1 ms latency timer.
New: tcp://host:port paths on every platform, ble:// (feature ble), dtr / rts options on open, SerialPort.scanBlePorts(); the plugin builds for iOS.

v2 → v3

In v2 you attached stream callbacks separately (startListening / listen / disconnected). In v3 one call — watch() — registers all of them; stop with the returned handle.

// v2
await port.startListening();
await port.listen((data) => console.log(data));
await port.disconnected((reason) => console.log("gone", reason));
await port.cancelListen();

// v3 — same thing in one watch()
const handle = await port.watch({
  onData: (data) => console.log(data),
  onDisconnect: (reason) => console.log("gone", reason), // replaces disconnected(fn)
});
await handle.unwatch();

v2	v3
`startListening()` + `listen(fn)`	`const handle = await port.watch({ onData: fn })`
`disconnected(fn)`	pass `onDisconnect: fn` into the same `watch({ ... })`
`cancelListen()` / `stopListening()`	`await handle.unwatch()`

Legacy Tauri events (plugin-serialplugin-read-*) and Android plugin triggers (serialData, serialError) are no longer part of the public API.

New in v3: SerialPort.getCapabilities() — { transport, platform, version } from Rust (cfg!), if the app needs to branch by platform (replaces ad-hoc window / @tauri-apps/plugin-os probing on the app side).

Breaking API changes (v3):

Field / behavior	v2	v3
`AtCommandResult.raw` / `ExchangeResponse.raw`	`number[]`	`Uint8Array`
`AtCommandResult.timedOut`	literal `false`	`boolean` (timeouts surfaced by native layer)
`open()`	`void`	returns canonical path (Android re-keys to `UsbPath.sessionKey`; desktop echoes input)
`cancel_read`	also detached watch on some builds	does not unwatch — use `close()` or `handle.unwatch()`
TX queue after error	port could stay halted until reopen	next `exchange` / `sendAt` job runs normally (`stopOnError` only stops remaining phases in one `sendAtPhases` batch)
Early RX before `exchange`	often lost or raced with wait	native hub keeps idle bytes; `exchange` replays them via `take_idle_bytes` after write (no extra line response needed)

AT API (v3)

Was	Now
`port.at.enqueue('AT')`	`port.sendAt('AT')`
`port.at.enqueuePhases(...)`	`port.sendAtPhases(...)`
`port.at.sendSmsPdu(...)`	`port.sendSmsPdu(...)`
`port.at.cancel()`	`port.cancelAt()`
`new SerialPort({ atSession })`	`atSession` still applies on `open()` via `configureAtSession`
Parallel `exchange()` throws	`exchange()` awaits turn in native queue

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DTR / RTS on open

Choosing the modem line levels when a port opens.

Changelog

All notable changes to tauri-plugin-serialplugin and tauri-plugin-serialplugin-api.