This is a high-level summary of changes between each release. If you're interested in the detailed changes, take a look at the individual code changes.

Feb. 25, 2010

Main release 0.3.16b

• Snap to grid (experimental, switch it on in the View menu)
• Use arrow keys to move parts around (hold Shift to move by ten steps)
• Improved rats nest coloring (less obtrusive, and more reliable dimming if a net has been routed)
• Replaced zoom widget by a nice slider
• Now fits on netbook screens as well (side-effect of the above)
• New parts: RGBB LED, LCD screen, slider pot, small rotary knob pot, Arduino pico (thanks to Brian Evans), more mystery parts
• Dutch translation (thanks to Steven Noppe)
• Bug fixes

Feb. 3, 2010

Main release 0.3.15b

• Chinese (Traditional) translation thanks to Robert Lee
• Bug fixes
• Linux version built with Qt 4.6.1

Dec. 23, 2009

Main release 0.3.14b

• new parts: mbed microcontroller
• part search
• snappier graphics performance courtesy of Qt 4.6
• bug fixes

Dec. 11, 2009

Main release 0.3.13b

• New parts: Arduino Mega, XBee, ADXL accelerometer
• Add text and images to pcb silkscreen for gerber export--this feature is still experimental
• Resizable redesigned ruler
• New examples: MIDI Drum Kit, Parking Assistant
• Bug fixes

Nov. 26, 2009

Main release 0.3.12b

• more new parts
• mystery parts with choice of footprints
• export etchable includes board outline
• print and export pdf now handle sketches bigger than a printer page
• new ground and power symbol behavior in schematic view
• bug fixes, including a couple of crash-bugs

Nov. 6, 2009

Main release 0.3.10b

Note this update fixes an error in 0.3.9 which we posted just hours ago. Sorry!

• Revised footprints for many parts (bigger pads for easier manual production)
  • In order to make use of them in existing sketches, click on "Part > Select outdated parts".
• New parts:
  • Customizable DIP & SIP ICs (no need to fiddle with the graphics outside of Fritzing anymore)
  • Customizable Resistor (any value is now allowed)
  • Editable labels for DIP, SIP and mystery parts
  • Pin headers, screw terminals and mystery parts in any length
  • Web-based part generator is therefore now obsolete
  • RFID reader module (thanks Tuommo)
  • DIN-5 MIDI jack
• Many parts editor bug fixes
  • Connector editing should finally work reliably
  • Resizable, so that you have more space to look at a part
• Real jumper wires with pads (for PCB layout, placed manually or during autorouting)
• More translations
  • Russian translation (thanks Vladimir)
  • Chinese (Simplified) translation (thanks Ninjia and Yuelin)
  • Japanese translation (thanks Hiroshi)
  • Portuguese (European) translation updated (thanks Nuno)
• ..and a lot more bug fixes and improvements.

Sept. 18, 2009

Main release 0.3.8b

• fixed some parts
• Portuguese (European) translation (thanks Nuno)
• bug fixes
• new parts (including a new breadboard--thanks Giuliano)

Aug. 14, 2009

Main release 0.3.6b

• change the background color of a fritzing view (in the view menu)
• Connector highlighting indicators can be changed from the standard red/green colors (in the preferences dialog)
• ground and voltage symbols in schematic view
• parts editor connectors an terminal points behavior improved
• friendlier illustrator import inside parts editor (origin translation)
• allMyParts bin generated on startup (to avoid user parts references loss)
• Projects uploading in the webpage
• many bug fixes

July 3, 2009

Main release 0.3.5b

• Shift-dragging parts constrains movement to vertical or horizontal
• Shift-dragging wires constrains the wire to 45° angles (also snaps to right angle lines when dragging a bendpoint)
• Double-click to add/remove bendpoints
• Support for fonts (for use in your part graphics - standard fonts supplied)
• Parts Editor automatically converts pixels to inches (no need to do this by hand anymore!)
• Autorouter now tries to route to previously routed traces and bendpoints, and routes ground traces last
• Schematic view shows proper thick junction points
• Tips & Tricks in the Help menu (for some handy shortcuts)
• New parts: 74HC595 IC, new Arduino schematic
• Parts library reordered (hopefully more sensible now)
• Export jpg/png with white background
• updated to Qt 4.5.2
• Bug fixes (including the Gnome dock activation bug)

June 23, 2009

Main release 0.3.4b

parts editor crash bug fixed

ground fill generator ignores grounded traces

notes more visually consistent across platforms

wire clipping bug fixed

June 18, 2009

Main release 0.3.2b

Exporting and importing part bins (for easier exchange)

Simple ground fill for PCBs (to make production less wasteful)

New part: Ruler (for simple measuring)

New examples: Op-Amp, Touch Switch (and lots of cleanup on the others)

Visual improvements to schematic view

Add a part to a bin directly from the sketch

Change wire color through context menu

Linux launch script compatible with all shells (thanks to ktq for the hint)

Many bug fixes, e.g.: svg exports, autorouter, parts editor (thanks to Shigeru for finding some of them)

June 2, 2009

Main release 0.3.1b

User parts & bins are now stored in the app folder (makes updating Fritzing less painful for you)

Create bendpoints by simply dragging them out of a wire (also the bendpoints' look has been tuned)

Highlighting of equipotential connectors (when you mouse-down on a connector)

Highlighting of unconnected connectors in red (thanks for the suggestion, Kai)

Schematic view workflow now similar to PCB (with rat's nest and autoroute)

Rotating breadboard/Arduino/PCBs (even with parts connected)

Tweaks and bug fixes (particularly a couple of 0.3.0 crash bugs: thanks to jdolce, merlin13, and kotobuki for alerting us; also thanks to d.toliaferro for alerting us to another one)

May 19, 2009

Main release 0.3.0b

• Resizable and custom-shaped boards (just import one as svg) - Note: You now get a rectangle PCB by default, swap for the Arduino Shield if you need it
• Gerber export (for sending your PCB to professional production)
• Multiple parts bins (and more: shareable bins, parts import, drag'n'drop reordering)
• Big performance boost (thanks to a new release of Qt)
• New part: Relay (and did you see the web-based parts generator at http://fritzing.org/parts/generator?)>
• Italian translation (thanks Gianluca!)
• Rotate boards (as long as they are empty)
• Lots of other tweaks and fixes

April 2, 2009

Main release 0.2.5b

• New parts: Pin headers
• Parts Editor restyling
• Bug fixes

March 24, 2009

Main release 0.2.3b

• New parts: Arduino Nano, header pins/holes, screw terminals, tilt switch, antenna, USB plug, power plug,
• First contributed parts: Stepper Motors from petbom!
• Examples have descriptive notes with links
• Mismatching connectors in parts editor: can be automatically fixed
• Changing properties on a part now selects closest match instead of giving warning message
• Bug fixes

March 4, 2009

Interim release 0.2.2b

• Shareable import was broken
• Fat rat's nest wires in 0.2.1
• Some new parts caused export failure

Feb. 27, 2009

Interim release 0.2.1b

swapping was broken under linux and windows

Feb. 26, 2009

Main release 0.2.0b

• the new parts editor is officially released
• french translation
• new parts
• many bugs fixed; many bugs created

Feb. 12, 2009

Interim release 0.1.17b

• major parts editor improvements
• better synchronization between schematic view and the other views
• new mouse hover behavior
• part swapping menus ordered numerically, when applicable
• "tiny" and "half" breadboards added
• added "mystery" parts as placeholders for parts Fritzing doesn't have yet

Feb. 1, 2009

Interim release 0.1.16b

mac manual trace wrong color bug fix updated german translation

Feb. 1, 2009

Interim release 0.1.15b

draw traces directly in pcb view traces aren't automatically cleared when there are changes to the board (deleting parts or connections still removes traces) export-etchable (was export diy) bug fixes simple text notes spanish translation (thanks to Kurt Badelt) some new and improved parts check for updates new examples

Jan. 21, 2009

Interim release 0.1.14b

swapping was broken in 0.1.13b

Jan. 20, 2009

Interim release 0.1.13b

two bug fixes around delete:

• delete followed by view switch was crashing
• delete followed by undo in pcb view was generating phantom parts

Jan. 18, 2009

Interim release 0.1.12b

• fixed some cases in which the autorouter was incorrectly unable to route a trace
• after the autorouter completes a trace, a clean-up function tries to eliminate some of the unnecessary zig-zags
• the connection currently being traced is now highlighted
• there's a 'stop this trace' button (next to the cancel autoroute button). if the autorouter gets stuck for too long on a particular trace (or you can see from the highlight that the trace would be blocked), clicking 'stop this trace' turns the current trace into a jumper wire, and the autorouter goes on to the next trace.

Jan. 17, 2009

Interim release 0.1.11b

New stuff

• Bill of materials export (to text file)
• Simple labels for parts (more UI work to be done)
• New examples for Optocoupler and Voltage Regulator

Some major bug fixes

• Autorouter: Jumping traces after autorouting (resulting in crossed wires)
• Autorouter: Routing stopped before completion (certain parts were mistakenly treated as having buses)
• Autorouter: Shift-click to remove bendpoint on traces crash
• Export DIY: Wires not lined up propertly with parts they were connected to
• Export DIY: Certain parts disappeared from export
• Delete/undo bug causing view desynchronization
• Part bug fixes on Optocoupler, Transistors

Jan. 9, 2009

Main release 0.11b

• Fixed a nasty copy/paste bug that could destroy your sketch (issue 409)
• Fritzing in your language! Starting with German, more to follow.
• Preferences dialog, currently just for language setting
• New parts: H-Bridge, ATmega168, Temperature Sensor
• IC part generator (so far only for experts, in the SVN)
• ...and a number of further fixes and enhancements

Dec. 23, 2008

Main release 0.1b

The "Fritzmas" release is the first version of the new Fritzing that we tend to call stable. We put a lot of effort into polishing, bug fixing, performance improvements and future-proofness (which also means that sketches created with older versions are not compatible with the new one).
We intend to circulate it on a wider base and are encouraging you to try it out on more serious projects.

• (Hopefully) clearer UI: We put some effort in making the "three views"-concept more understandable, with a new view switcher, miniature views in the navigator, cross-view icons in the inspector, and a new help text on opening Fritzing for the first time.
• New website: Based on a new underlying web framework (Django), the new website is the foundation for the upcoming social features. Soon you will be able to share projects and custom parts.
• Refined .fz file format that is (more likely) future-compatible
• New parts (big potentiometer, batteries, dc motor) and lots of clean-up
• Five new example sketches, including a Fritzmas surprise
• Improved synchronization of views (especially for schematic view)
• New overall design and styling, with much more space for your sketch
• Big speed-up for the breadboard
• Export DIY is now vector-based and faster
• Improved autorouter
• Breadboard parts resized to be closer to actual size
• Parts editor connectors view allows for zooming and panning
• Connectors, connections, buses, and wires cleaned up
• Autorouting can now be undone
• ..and many more big and small bug fixes 

Nov. 24, 2008

Main release 0.1b

Lots of improvements :)

Nov. 12, 2008

Main release 0.1b

First preview release of the all-newly programmed Fritzing.