I have released qpdf version 4.2.0.  This is mainly a bug fix release with a few small enhancements.  The major thing here is a fix to a bug that would result in the loss of compressible objects whose generation numbers were greater than 0 when generating object streams.  In addressing this problem, I added some better API calls for handling object ID and generation together as a QPDFObjGen, which should reduce the likelihood of other people coding similar bugs.

Other changes include the addition of --show-npages to the qpdf command-line tool, some improvements to the command-line parsing of the --pages option, and several small enhancements to make qpdf able to handle a wider range of broken input files.  Full details can be found in the release notes at http://qpdf.sourceforge.net/files/qpdf-manual.html#ref.release-notes.