Why doesn Eclipse 2.1.x work with CVS server versions 1.11.7 and beyond?
Most of the interesting Eclipse CVS functionality relies on the format of the messages and the change in format made in 1.11.7 breaks the parsing in Eclipse versions prior to 2.1.3. Most of the incompatibilities for 1.11.x were addressed in 2.1.3. See bugs 46655 and 49056 for patches and workarounds for previous versions of Eclipse or remaining incompatibilities. As for 1.12.x releases of CVS, Eclipse 2.1.x is not compatible with this server version. Eclipse 3.0 is compatible with 1.12.7 but future releases of CVS may cause similar breakages. In such cases, Team>Update and Team>Commit should still work but the more advanced work flows (e.g. synchronizing) may not be reliable.