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Upgrade Guide

Upgrading from 9.x to 10.x

This release brings a few major changes to the SerialPort family of packages.

  • N-API Support for our hardware bindings
  • TypeScript Types for all packages
  • New Bindings interface
  • Dropped support for Node 10
  • All packages now have named exports. They export their types and all relevant classes.

SerialPort package

This release has breaking API changes but they're relatively minor. Most behaviors are exactly the same. You can find details at the 📦 serialport docs.


const SerialPort = require('serialport')

has changed to;

const { SerialPort } = require('serialport')
// or for esm
import { SerialPort } from 'serialport'


Parsers are also no longer on the SerialPort.parsers object and can be found as exports of the serialport package.

const ByteLength = SerialPort.parsers.ByteLength

has changed to;

import { ByteLengthParser } from 'serialport'


The constructor no longer has an optional baudRate (The old default of 9600 was slow and usually not what's required.). Because of this we combined the path into the options object and made it required.

new SerialPort('/dev/port')

has changed to;

new SerialPort({ path: '/dev/port', baudRate: 9600 })


SerialPort.Bindings is now read only and bindings is no longer part of the options object. You can no longer apply custom bindings to the SerialPort class but you can use SerialPortStream from the @serialport/stream package if you need this functionality.

Test Object

To get a test SerialPort class you can now import a SerialPortMock class instead of requiring a test file. This class comes preloaded with the MockBinding class from @serialport/binding-mock.

const SerialPortMock = require('serialport/test')

has changed to;

const { SerialPortMock } = require('serialport')
// or
import { SerialPortMock } from 'mock'

Bindings Packages

  • @serialport/bindings has been renamed to @serialport/bindings-cpp. It is shipped with prebuildify and no longer require a post install to download the binaries, but instead they're all included in the npm package.
  • @serialport/bindings-cpp leverages N-API and shouldn't need to be upgraded for every node release or rebuild for electron
  • Bindings in general now have a new interface with the @serialport/bindings-interface type package that replaces @serialport/bindings-abstract


  • SerialPortStream from @serialport/stream no longer has a list() method as that was a direct call to the bindings.
  • SerialPortStream methods (and by extension SerialPort methods) no longer throw when called with invalid input, their callbacks or the error event will convey input errors. This is because the binding layer now handles input validation as it's different on each platform.
  • @serialport/terminal no longer has a default baudRate

Upgrading from 8.x to 9.x

  • Serialport no longer supports Node 8
  • We no longer provide 32 bit linux prebuild builds, you may still build these binaries yourself however.

Upgrading from 7.x to 8.x

  • Serialport cli tools are now their own packages. See for more information on how to use them.
  • SerialPort.list() and Bindings.list() no longer take a callback and only return a promise.
  • comName has been renamed path in the PortInfo objects returned from SerialPort.list() or Bindings.list() you'll get a deprecation warning if you access comName until the next major version where it will be absent.
  • @serialport/terminal now takes a --path argument instead of a --port argument
  • Bindings now use async functions and no longer throw errors, they only reject errors. If you relied on this behavior you can now simplify your code to only looking for promise rejections.

Upgrading from 6.x to 7.x

We dropped support for Node.js 4, so you'll have to upgrade if you're running 4. We also split into many packages. See for an overview of the new packages. Binaries have moved into @serialport/bindings so if you're distributing serialport in an electron app, you may have to make some changes.

Upgrading from 5.x to 6.x

TLDR: You probably don't have to change anything. You might need to enable rtscts in your open options.

  • binaries: We switched to prebuild a breaking change because it's substantially changes our install processes. It's also possible the install flags to ensure downloading or building from source has changed slightly. That's not our api per se, but it's enough for a breaking change.
  • windows: We previously hard coded to have RTS on for windows at all times it now default to off.

Upgrading from 4.x to 5.x

Node SerialPort 5.0.0 is a major rewrite that improves stability, compatibility and performance. While the api surface is similar there have been a number of changes to ensure consistent error handling and operation of a serial port.


  • Drop NodeJS 0.10, 0.12, 5, and 7 support
  • Add node 8 support (we now only support LTS node versions)

The SerialPort Object

  • Node SerialPort is now a duplex stream and can be paused and resumed on all platforms.
  • isOpen is now a property
  • SerialPort.list now has more consistent output across all platforms. This means the data in the objects may be different than 4x. Notably the path on OSX now returns the tty instead of the cu path and the 0x has been removed from values on linux and osx.
  • port.path is now read only
  • removed lowercase options all options are now only accepted camelCase
  • Changed parsers to be transform streams. There are replacements for the built in parsers but custom parsers will have to be modified.

Open options

  • bufferSize is now highWaterMark and defaults to 64k.
  • parser is removed in favor of using the new transform streams parsers

Opening and closing

  • Removed the disconnect event. The close event now fires with a disconnect error object in the event of a disconnection.
  • port.isOpen is now a property not a function

Reading and writing

  • port.on('data') still works but and the readable event is now the preferred way to get data.
  • is now the best way to read data
  • port.drain() now waits for the current javascript write to complete before calling the system level drain.


  • We now conform to NodeJS error message formats. Most messages have changed.
  • The event loop is no longer held open if there are no active reads or writes
  • SerialPort.list has slightly different output with more information, decoded strings and 0x prefixes removed from some properties.
  • SerialPort.list now returns a promise if no call back is provided

Upgrading from 3.x to 4.x

4.x brings a lot of changes please see the changelog for the full list of changes. We'll review the api and behavior changes here.

The constructor has changed. We've removed an argument, changed how errors are thrown and it is returned when you require('serialport');

  • Requiring serialport now returns the SerialPort constructor function instead of a factory object. SerialPort.SerialPort is now deprecated.

  • SerialPort constructor now throws on argument errors immediately.

  • Removed openImmediately from the constructor's api, the functionality is now named autoOpen on the options object.

  • Removed extraneous flow control settings from the flowControl option, use the specific options to set these flags now.

  • Removed undocumented callbacks from the options object disconnectedCallback and dataCallback

    Write had a major change

  • .write(writeCallback) now only calls it's callback once after the entire write operation, it used to be called for each write cycle and return the bytes written. This reduces the number of callbacks by hundreds of thousands over a megabyte at low bandwidth.

Callbacks changed a little

  • All callbacks are called in the context of the port, this now equals the port.
  • Disconnections now always attempt to close the port, and you'll always get a close event after a disconnect event

Renamed our binaries

  • Renamed serialportlist to serialport-list
  • Renamed serialportterm to serialport-term

We fixed a bunch of bugs too

  • [unix] .drain and .set now properly report errors
  • [windows] Fixed a bug where we weren't properly opening ports (provides better support virtual com ports too) thanks to @RogerHardiman
  • [windows] known issue lock false doesn't work (no change in behavior)

And added a new features

  • [unix] Ports are now locked by default with the new lock options matches windows default behavior
  • [windows] .update() now supports windows for changing baud rates

Upgrading from 2.x to 3.x

3.0 brought a single major breaking change and a lot of minor improvements.

We stopped removing event listeners, if you wrote code to work around that, we're sorry we made you do it.

  • close and disconnect events no longer call removeAllListeners and removes your event listeners. This was particularly bad for the error event. This is the only change and if you didn't have a special code to deal with this behavior you should probably upgrade from v2.1.2

New Features

  • Added support for node 6.0
  • Update the cli tools. serialportterm can now list ports, serialportlist can now output in different formats
  • [unix] Better unix error messages

Fixed bugs

  • [linux] bug fix in .list() where we weren't filtering out non block devices that are named like serial ports
  • [unix] Update now has less memory leaks, documentation and better error messages
  • [windows] Better error messages for opening ports