Things which come to mind (comparing roughly 2.8 (released 2010-07) to 2.11 (released 2013-03)):
Classes (just from the top-level scala.* package):
- scala.actors and subpackages
- scala.concurrent (still exists, but its contents have been replaced completely)
- scala.dbc and subpackages
- scala.swing and subpackages
- scala.util.parsing and subpackages (includes parser combinators and JSON)
The list is certainly incomplete anyway...