With every new CIAO release, it is likely that some parameter files have changed; new parameters may be added and occasionally old ones removed or renamed. In most situations, this should be picked up automatically by the CIAO parameter interface and you will see a message such as:

unix% plist ciao
Warning:  found possibly out of date user parameter file, renamed to /home/ciaouser/cxcds_param/ciao_20021113.09:29:58.par

... Normal output from 'plist ciao' ...

However, this is not guaranteed to work in all cases - in particular with scripts with a parameter interface - which may result in strange behaviour.

We therefore strongly recommend deleting the old parameter files or renaming the parameter-file directory before running any new version of CIAO. CIAO parameter files are generally stored in the directory $HOME/cxcds_param4/.

Note that the CIAO 4.0 software establishes a separate local parameter file directory by default, ~/cxcds_param4. This allows users to run both CIAO 3.4 and CIAO 4.0 without having to worry about parameter file conflicts.

More information on parameter files is available in the Introduction to CIAO thread.