I'm reading about the maven versions plugin : http://mojohaus.org/versions-maven-plugin/examples/advancing-dependency-versions.html
For this goal : "versions:use-next-releases searches the pom for all non-SNAPSHOT versions which have been a newer release and replaces them with the next release version."
What is meant by "have been a newer release", where is it searching for a newer release ? Is it checking against the central repository for a newer version ?
Yes, or your repository manager (such as Nexus or Artifactory) if you have set one up. You can also use display-dependency-updates to just view what the result would be without actually changing the pom itself. I found this to be more valuable as sometimes projects use slightly different numbering schemes then what Maven expects, so you could end up with a version you don't really want.