On 27-11-13 22:12, jonathan.labin wrote: I am not of anyone that tried besides you. If you want to be confident it's safe, do the following: git clone optaplanner cd optaplanner gedit pom.xml // in <dependencyManagement> overwrite the commons-collections dependency to 4.0 and save mvn clean install // runs all unit and integration tests in about 8 minutes (without the stress test that take 30 hours but don't cover more code) If the build succeeds, its fine. Probably not in the next release. IIRC Hibernate, EAP 6, etc are still using commons-collections 3.x, so it would be too early to jump to a new major release (a minor or hotfix release would be less trouble). Sooner or later, we will upgrade though. Side note: I am seriously considering of adding a guava dependency in optaplanner 6.1 and dump the commons-collections dependency altogether. https://issues.jboss.org/browse/PLANNER-209 Wdyt?