I just noted that 5.02.2 is binary incompatible with 5.02.1 which is a minor nuisance, since I must then recompile all my .o-files.

This was not mentioned in the release notes, perhaps it was unintentional?

Yes, this is the case for *all* releases of GHC, even minor ones(*). It would be nice to improve this situation, but unfortunately retaining binary compatibility is not straightforward due to the high level of coupling between compiled modules - the price you pay for aggressive inter-module optimistaion. Cheers, Simon (*) Actually this may not be strictly true, but binary compatibility would be accidental rather than intended.