On their website they claim the latest version is 2.3.2.0-SNAPSHOT, but I can't find the JAR anywhere. It's not in any of the repos (Maven Central, etc), no downloads page on their site, or anywhere else. If you check out the master branch from their GitHub git repo, it just contains source, but no libs.
Because it is a snapshot release, it is not in the central repository but in the sonatype snapshots one:
If you want your maven project to download it from this location you have to add the repository to your pom file:
<repositories>
<repository>
<id>sonatype</id>
<url>http://oss.sonatype.org/content/repositories/snapshots</url>
<snapshots><enabled>true</enabled></snapshots>
<releases><enabled>false</enabled></releases>
</repository>
</repositories>