bug fixes. Most of the minor releases are bug fixes. Major releases contain new features, - LimeWire usually posts the list of new changes in the beta forum for every major release.

For longer changelog, you can simply subscribe to the cvs@core.limewire.org and cvs@gui.limewire.org mailinglist, - but honestly - most users do not seem to care about it and I don't remember anyone - except for you and maybe one or two others in the forum - complaining about LimeWire's changelogs.