I have released qpdf 5.1.0. The main functional change here is the ability to provide your own source of random numbers at runtime if you want to avoid both the OS-provided secure random numbers (used by default since 5.0.1) and the older stdlib random numbers. This release also features a number of small fixes for newer versions of several compilers and to handle one more type of damage to a PDF file.  For details, please see the release notes in the documentation or the ChangeLog.