Hi Joachim, On Wed, Dec 12, 2012 at 12:20:35AM +0100, Joachim Breitner wrote: > there really a change to the on-disk format of the .haddock files? Yes, the on-disk format changed, hence the interface version was bumped from 21 to 22. But Haddock can still read files with interface version 21 (see [1]). Cheers, Simon [1] https://github.com/ghc/haddock/blob/ghc-7.6/src/Haddock/InterfaceFile.hs#L81