And here is the list of features and enhancements by OS :-
- fixing whitelist handling
- Added license header to new files.
- Remove unused files/classes until they are needed.
- Fixing scale, setting legacy scale
- Work-around Feature for Classic PhoneGap 320×480 resolution and more
- Added Battery core plugin to PhoneGap.plist
- Fixed CB-143 – Removing address from iOS contact causes crash
- Added ‘PhoneGap Upgrade Guide’ doc to the .dmg (as a PDF)
- Fixed CB-42 – MediaPlaybackRequiresUserAction can now be set to NO
- Added stand-alone PGViewController (Cleaver – PhoneGap as a Component)
Windows Phone :-
- Fix for single document – multipage layouts
- Added VERSION file to be like other platforms.
- Acceleromter fix #CB-141 – InvariantCulture
- Contacts returned from find were not formatted. CB-157
- Fixes for loading local XHR using file API, and still using default for remote XHR. responseXML returns document for local files.
- updated phonegap.js to include XHR updates
- Compass API fixes
We can get more details from here http://phonegap.com/2012/01/31/phonegap-1-4-released/