The latest release, Scala IDE 4.0.0, has been re-build on and re-packaged with the latest release of Scala: 2.11.5.
It contains the improvements provided by the new version of Scala. For more details, check the Scala release notes.
As usual, this build is available as an all-in-one bundle and through the update sites, for new installations.
Existing installations can be updated using the Help -> Check For Updates
feature.