Upgrading packages/Updating to GHC 6.10
A list of things that need updating when porting packages to newer library/cabal versions.
Updating to GHC 6.8 and Cabal 1.2
Cabal configuration support
Cabal API changes
Many packages that use non-default Setup.hs or Setup.lhs files need to be updated as they use Cabal APIs that have changed. In many cases new features in Cabal-1.2 allow these packages to go back to using the default Setup.hs.
A more detailed survey of the packages from the hackage collection is here: http://www.haskell.org/pipermail/libraries/2007-September/008265.html
base package split up
The base package was split up, and new dependencies are now required;
and more. Dealing with these is a simple matter of installing the packages from hackage, and updating the build-depends in your cabal file.
Data.ByteString api changes
module Data.ByteString.Base has been split into two. The "unsafe" functions moved to Data.ByteString.Unsafe and the others moved into Data.ByteString.Internal. The stable API going forward is all the modules exposed by the bytestring package except for the .Internal modules and the .Fusion module.
The lazy list representation type has changed.