JSPWiki version numbers are in the "version.revision.minorrevision" -style. Each of these values is an integer, therefore 2.0.0 is newer than 1.9.0 (because the "version" component is newer). 2.1.0 is newer than 2.0.99. In addition, 2.1.100 is newer than 2.1.99 (because 100 > 99).