PhoneGap announced today that they will deprecate PhoneGap 2.9 and older on October 15, 2014. Phone 3.0 and later are supported: the current version (as of the date of this post) is 3.6.3.
In most cases, the changes will not be major. Remember to go into your Project Properties and edit ‘PhoneGap config.xml’. It will have a line like this – edit it to use Version 3.6.3 (current as of the date of this post).
"<preference name=\"phonegap-version\" value=\"3.6.3\" />",
You can also delete the line entirely. In this case, PhoneGap Build will always use the latest version of PhoneGap.