It is an old issue, but recently with a switch to Maven it has become more critical, as libraries come with their version numbers in the names from Maven. Spark's installer is not removing older files when doing an update, so it will leave old versions of Smack, Jtattoo, etc, in the libs folder. It also leaves other files, like libs\windows folder on Linux (or linux folder on windows), though build process is already modified to avoid adding those to a not supported platform. Another problem is that Spark uses first version that it founds it seems, so when two versions of Smack are present, it may use the older one. Maybe installer can be instructed to remove previous versions of files, or files should use static names, so they are overwritten by the installer (but this won't solve an issue with old, not needed files being left behind).