I think the type of testsuite/tck failures we have been experiencing the last couple of weeks are indicative of how important those base libraries are (VFS/MC/Deployers/etc.) Although APIs may look constant it is inevitable that users of this code will depend on internal implementation details or specific dynamic behavior (e.g. threading invariances). So the lessons to be learned here are: - Be extra careful and conservative when changing base libraries. Local testing will almost certainly not reveal all the possible runtime outcomes and uses of the base library. - Good integration testing should always take place higher up the chain, either through some temporary Beta/CR release, or a versioned snapshot. E.g when changing jboss-common, the change might work for you but not for the other 15 projects using it. - Do your homework when using APIs from other projects. Ask for best practices in the forums, the authors are there to help. Looking at the stream of commit messages in the base project often gives me the shivers. It could be I'm just getting older but at the same time you need to remember that AS5 is already GA and should be treated as such. /Dimitris