With Gmail Growl V2.3, some new features are added:
Account specific notifications
Gmail Growl now registers "New Mail" notifications for each Gmail account separate. This allows different displays, forward settings etc. in Growl based on the account.
URL shortening with Goo.gl
Since a recent version of Growl, the URL to the message was added to the screen notification. The URL is needed for notifications forwarded to mobile devices. To reduce the amount of text displayed through Growl, the URLs are now shortened with Goo.gl.
Embedded experimental mini implementation of Growl
You can now use Gmail Growl without installing Growl for Windows. V2.3 contains a very basic experimental implementation of the Growl notification transport protocol (GNTP). There is no forwarding or networking and it only has a single display similar to the default display of Growl. The displays can be done without coding, but I did not have time to do a manual for this. If you like puzzles, just look at the files in Gmail Growl\MiniGrowl\displays.
In addition, Gmail Growl V2.3 fixes a display problem with the Windows 7 Taskbar icon where the unread items count was not removed when there were no unread mails.
Please note that for push notifications, Gmail Growl needs the "All Mail" label to be exposed by Gmail through IMAP. If you have disabled this using the Google Labs feature "Advanced IMAP Controls", then push notifications do not work in Gmail Growl. This version contains a specific check for this situation.