Message12080

First a hint on upgrading a single dependency:
To upgrade jnr, replace the jar in extlibs folder with the version you intend. Then search build.xml for the name of the old jar and replace each occurrence with the new name. Then run ant build, or ant jar-standalone or ant installer or whatever target you need.

Regarding hooks:
I don't have capacity to get into jnr internals now. If you know what hook you'd like to add, which method you need to call at which point we can iterate again.

Regarding Jython 2.7.1:
I recommend to keep investigating an update path. File issues here if it's Jython's fault breaking your plugins. If it has to do with pyc files -- I'm surprised you rely on pyc files -- an important change is that Jython 2.7.1 now supports (and requires) Python 2.7 bytecode while Jython 2.7.0 still  used Python 2.5 bytecode. So maybe you just need to rebuild your pyc files with CPython 2.7. pyc bytecode underlies backwards incompatible change between Python 2.5 and 2.7.