Cervisia requires cvs 1.10 on the cvs server. With cvs 1.9, diffs don't work! As this old version has a y2k bug, switching is advisable anyway. From version 1.1 on, Cervisia implements the menu item File->Revert. This hands over the command 'cvs update -C' to the cvs client. This works only for cvs >= 1.11. Bug reports are welcome. My time is limited, so don't expect wonders. If you want to contribute bugfixes or improvements, check out the source code from anonymous kde cvs. In order to bootstrap the package, you have to 'make -f Makefile.cvs' there. Then you can make patches either by using 'cvs diff -u' or by using the 'Create patch' menu item in Cervisia. Christian Loose