Changes worth mentioning:
Everything
- Fixed Spanish translation error in disk image background
- Replaced GrowlMail in Extras folder with a link to the GrowlMail web page, since it's now separate from Growl releases
Growl
- Handles old plug-ins you can't use anymore more sanely
- Fixed MailMe display generating invalid messages, which may manifest as receiving blank messages or messages getting eaten by mail servers
- Speech display now reads notification titles as well as descriptions
- Speech display now obeys the rate set in the Speech prefpane (#112)
- WebKit-based displays are now much, much faster
- WebKit-based displays can use frames and relative URLs now
- Fixed the positioning hang (#103)
- Worked around a bug that caused WebKit-based display windows to sometimes be only 1 pixel tall (#108)
- Fixed forwarding recipients not being able to listen for connections
- Fixed a crash when trying to load application tickets with no application name, reported by Hannes Mannerhiem
- Growl now automatically detects when you put plug-ins in the PlugIns folder yourself
- Added a sample display plug-in for Cocoa display developers
- Fixed bogus disabling of plug-ins that shouldn't have been disabled
- Fixed bogus disabling of MailMe when you have no sending accounts set up in Mail
- Updated the “Get More Styles” link on the disk image
- Added a version string to the MailMe display
- Fixed a whole lot of memory leaks
GrowlSafari
- Restored your ability to click a “Download finished” notification to reveal the downloaded file in the Finder (#118)
- Now has an icon
GrowlTunes
- Fixed a hang on Snow Leopard under certain circumstances (#114)
- Fixed notifications that don't have album art showing the iTunes for Mac OS icon when iTunes for Mac OS is installed
- Ripped out code supporting old versions of iTunes; GrowlTunes now requires iTunes 4.7 or later
- Fixed GrowlTunes notifying while iTunes is the active application (#112)
Growl.framework
- Updated minimum OS version for Growl, preventing bogus installation prompts
- Only ever register with a running GrowlHelperApp, never a GHA that isn't running
- Fixed memory leaks
HardwareGrowler
- Fixed warnings and analyzer flags
growlnotify
- Now uses an Installer package for installation
BeepHammer
- Fixed leaks and other bugs
All the changes: http://growl.info/documentation/version_history.php