Andreas Jaeger <aj(a)suse.de&gt; writes in xemacs-beta(a)xemacs.org: <major>.<minor> where <minor> is alphabetically sortable from 0 to 99. <major> gets incremented any time there is a major incompatible change and should be done sparingly. The numbering was introduced because there are so many different ways authors number their version and I felt that it would be intrusive to insist that version numbers appear in a certain format (or to force version numbers at all, for that matter). No. The number has to change every time a new release is made because the MD5 hash of the tarball will change and make the package-index file out of date. Keeping the package-index file in synch has been a _major_ problem so far. The <minor> number increases every time a new tarball is created to put in the packages/ directory on ftp.xemacs.org. Please feel free to direct any other questions you might have about the numbering to me.