The major new features are:
- New plugin architecture – even the base APIs – like accessing the camera or address book – have been extracted to plugins so you can include the neccessary APIs only, which should result in a reduced app size.
- New CLI tools with integration of PhoneGap Build, so you don’t have to install the platform SDKs locally.
- Support for iOS6, Windows Phone 8, and BlackBerry 10. Support for iOS7, Firefox OS and Ubuntu will follow.
- New APIs: InAppBrowser and Globalization.
For further details, take a look at the official announcement.