The JetGroovy plugin is now bundled with IntelliJ IDEA. Please remove the version of the plugin you have in config/plugins.
Introduce Parameter Object
The "Introduce Parameter Object" refactoring (previously part of Refactor-J 2.0) is now available in IntelliJ IDEA.
CSS support is now packaged as a separate plugin which can be turned off if you don't use IntelliJ IDEA for Web development.
Plugin Loading Policy
If a plugin with the same name is available both as a bundled plugin and as a user plugin under config/plugins, IDEA now loads the plugin which has a later version. Previously, the user plugin was always loaded.
Bundled plugins can no longer be uninstalled - they can only be disabled.