The Groovy tool JSON (http://mirror.xmission.com/jenkins/updates/current/updates/hudson.plugins.groovy.GroovyInstaller.json, e.g.) doesn't have any natural sorting of its own - it just takes the list from https://dl.bintray.com/groovy/maven/ and spits it out in reverse order. That'd be great if that list itself was usefully sorted, but, well it's alphabetically sorted on filename. Which would be fine if the filenames all started with the same thing, but the pre-Apache ones all start with "groovy-" while the Apache ones start with "apache-groovy-", so 2.4.4 and 2.4.5 end up alphabetically ahead of 1.5.0, etc. We should sort based on the version, regardless of the source page's sorting.