Download Links:
Windows
Mac OS X
Linux (32 Bit)

Release Notes:

0018 – 2010.01.29

[core / libraries]

* Added tone() and noTone() functions for frequency generation.
* Added Serial.end() command.
* Added precision parameter for printing of floats / doubles.
* Incorporated latest version of Firmata.
* Fixed bug w/ disabling use of the RW pin in the LiquidCrystal library.
* No longer disabling interrupts in delayMicroseconds().
* Fixed bug w/ micros() returning incorrect values from within an interrupt.
* Fixed bug that broke use of analog inputs 8-15 on the Mega.

[environment]

* Synchronized with the Processing 1.0.9 code base, bringing various fixes,
including to a bug causing saving to fail when closing the last sketch.

* Added support for third-party hardware in the SKETCHBOOK/hardware folder,
mirroring the current structure of the hardware folder in Arduino.

* Added Ctrl-Shift-M / Command-Shift-M shortcut for serial monitor.

* Hold down shift when pressing the Verify / Compile or Upload toolbar
buttons to generate verbose output (including command lines).

* Moving build (on upload) from the applet/ sub-folder of the sketch
to a temporary directory (fixing problems with uploading examples from
within the Mac OS X disk image or a Linux application directory).

* Fixed bug the prevented the inclusion of .cpp and .h (or .c and .h) files
of the same name in a sketch.

* Improved the Mac OS X disk image (.dmg): added a shortcut to the
Applications folder, a background image with arrow, and new FTDI drivers.

Interested in setting up the Arduino IDE to work on Ubuntu 9.10?

Head over to codetorment for a step by step guide for Ubuntu 9.10 32bit edition.

Download it For Windows, Mac OS X, and Linux 32Bit.

Arduino Software Release Notes

0017 - 2009.07.25

[documentation / examples]
* Many new and revised examples from Tom Igoe.

[core / libraries]
* Updated LiquidCrystal library by Limor Fried.  See reference for details.
* Updated Firmata library to version 2.1 (rev. 25).
* Replaced the Servo library with one (MegaServo) by Michael Margolis.
  Supports up to 12 servos on most Arduino boards and 48 on the Mega.
* Improving the accuracy of the baud rate calculations for serial
  communication (fixing double-speed problems on 8 MHz Arduino boards).
  Thanks to gabebear.

[environment]
* Synchronized with the Processing 1.0.3 code base (rev. 5503), bringing
  many improvements (listed below).
* New icons and about image by Thomas Glaser (envis precisely).
* Support for multiple sketch windows.
* The serial monitor now has its own window.
* Comment / Uncomment menu item (in Edit) and keyboard shortcut.
* Increase and Decrease Indent menu items (in Edit) and keyboard shortcuts.
* Support for third-party libraries in the SKETCHBOOK/libraries folder.
* Libraries are now compiled with the sketch, eliminating the delay when
  switching boards and the need to delete .o files when changing library
  source code.
* Arduino now comes as an app file (in a dmg) on the Mac.
* Adding the Arduino Nano w/ ATmega328 to the Tools > Board menu.

Arduino 16 IDE Released!

Download for:

Windows | Mac OS X | Linux (32 Bit)

Arduino Software Release Notes

0016 - 2009.05.30

[documentation / examples]
* New communication examples (w/ corresponding Processing and Max/MSP code) by
  Tom Igoe.

[core / libraries]
* Adding support for the Arduino Pro and Pro Mini 3.3V / 8 MHz w/ ATmega328.
* Adding support for the LilyPad Arduino w/ ATmega328.
* Adding write(str) and write(buf, size) methods to Print, Serial, and the
  Ethernet library Client and Server classes.  This allows for more efficient
  (fewer packet) Ethernet communication.  (Thanks to mikalhart.)
* Improvements to the way the Ethernet library Client class connects and
  disconnects.  Should reduce or eliminate failed connections and long
  timeouts.  (Thanks to Bruce Luckcuck.)
* Optimizing the timer0 overflow interrupt handler (used for millis() and
  micros()).  Thanks to westfw and mikalhart.
* Fixing bug that limited the bit() macro to 15 bits.  Thanks to Paul Badger.
* Adding ARDUINO version constant (thanks to prodding from mikalhart).

[environment]
* Ordering the items in the Tools > Board menu.
* Adding "Copy as HTML" command to the Tools menu.
* Eliminating (maybe) the occasional "Couldn't determine program size" errors.
  Thanks to the Clever Monkey.
* Moving selection of Linux look-and-feel into the arduino script so it can
  be changed by users.  Thanks to Eberhard Fahle.

[tools]
* Adding automatic dependency generation to the Makefile.  (Lars Immisch)

With the release of the new Arduino MEGA, we have a new version of the IDE.

Download the Windows, Linux or MAC OS X verison.

Release notes:

0015 – 2009.03.26

[core / libraries]
* Adding support for the Arduino Mega (ATmega1280).

[environment]
* Reinstating use of core.a library in the build process, slightly shrinking
compiled sketch sizes. (Thanks to William Westfield.)
* Fixing bug in copy for forum (thanks to eried).

Overview of the new Arduino Mega:

The Arduino Mega is a microcontroller board based on the ATmega1280 (datasheet). It has 54 digital input/output pins (of which 14 can be used as PWM outputs), 16 analog inputs, 4 UARTs (hardware serial ports), a 16 MHz crystal oscillator, a USB connection, a power jack, an ICSP header, and a reset button. It contains everything needed to support the microcontroller; simply connect it to a computer with a USB cable or power it with a AC-to-DC adapter or battery to get started. The Mega is compatible with most shields designed for the Arduino Duemilanove or Diecimila.

via Arduino – HomePage.

2009.03.11 Arduino 0014 for Windows and Mac OS X available from the software page. This is a minor bug fix release.
Arduino Software Release Notes

0014 – 2009.03.07
[core / libraries]
* Fixing bug that prevented multiple outgoing Client connections with the
ethernet library.

[environment]
* Clarifying ATmega168 vs. ATmega328 in the Tools > Boards menu.

[tools]
* Updating the Mac OS X AVR tools to AVR MacPack 20081213. This includes
avr-gcc 4.3.2, which should fix problems with functions called from
within interrupts.