+\item removed the @PrimIO@ type. For a limited time only, @PrimIO@
+ will be available from @GlaExts@ as a synonym for @IO@.
+
+\item changed the type of @_ccall_@s to return @(IO a)@.
+
+\item renamed @mainPrimIO@ to @mainIO@, as it now has type @IO ()@.
+
+\item fixed the semantics of the @-i@ flag to @mkdependHS@ to be the
+ same as GHC.
+
+\item fix panic when a type constructor is used as a class.
+
+\item don't arbitrarily truncate cost centre names in profiling information.
+\end{itemize}
+
+In 2.09, we've made extensive changes to the libraries that provide
+access to various GHC extensions. Many of these extensions are now
+provided by Hugs, and as a result we are now using a common set of
+extension libraries.
+
+Briefly, the changes are as follows (for the definition of the new
+libraries, see the section on GHC/Hugs libraries in the User Guide).
+
+\begin{itemize}
+\item Addr moved out of Foreign and into its own module.
+
+\item MutVar module disappeared, IOExts now exports IORefs and associated
+ operations.
+
+\item The @CCallable@ and @CReturnable@ classes now have their own
+ module, @CCall@. You only need to import this module to provide a
+ new instance of one of these classes.
+
+\item A new module @IOExts@ provides extensions to the @IO@ monad,
+ including @unsafePerformIO@, @unsafeInterleaveIO@, @IORef@s (mutable
+ variables), and @IOArray@s (mutable arrays).
+
+\item Importing @ST@ is now the official way to get access to the @ST@
+ monad. This module also supports @STRef@s (mutable variables) and
+ @STArray@s (mutable arrays).
+
+\item A new module @LazyST@ provides an identical interface to @ST@
+ except that the underlying implementation of the monad is lazy. Be
+ careful about mixing these two in the same program.
+
+\item The new module @Bits@ provides a class of bit operations. The
+ modules @Int@ and @Word@ provide signed and unsiged integer types
+ (respectively) of varying sizes, all of which support bit
+ operations.
+
+\item Added @Bits@, @Int@, @Word@ (and a few new primops over words).
+
+\item The @GlaExts@ module will provide Glasgow-only extensions. For
+ now, we've kept the old interface for compatibility, but beware that
+ this is deprecated and the relevant extension libraries should be
+ imported explicitly.
+
+\item Several changes to the libraries in @lib/ghc@ - see the User
+ Guide for details.
+\end{itemize}