6.10.3 is a bugfix release over 6.10.2. Very few changes have been make. They are listed below.
Control-C now works again in GHCi. In 6.10.2 it was ignored on some platforms due to the changes in signal handling.
GHCi uses Haskeline, rather than editline, for line editing. This fixes a crash when pressing control-C on some platforms, removes a C library dependency, and provides a better user interface.
It is now possible to build PDF and PS versions of the users guide, using dblatex.