@markhamstra's right, the subproject POMs inherit the version number from the [`<dependencyManagement>` section of the root POM](https://github.com/mateiz/spark/blob/f117dc6d0d1349c28b7e1c8cf7729d1aafde5d25/pom.xml#L379), and should not explicitly mention the version in the subproject's POM.