"Zope 2.3.1b3 contains a number of bug fixes, including fixes
for issues found during b2 regarding ZCatalog and updating
ZCatalogs to make use of new underlying data structures. For more
information on upgrading ZCatalog objects."
"**Users of the Zope source releases should note** that this
release contains changes to existing C code. If you are using a
source release (or the source diff update), be sure to run
'w_pcgi.py' or 'wo_pcgi.py' as appropriate before starting Zope to
ensure that your binaries are rebuilt."