I have a project which declares a dependency on org.jenkins-ci.lib:lib-jenkins-maven-embedder. With 3.7 it worked fine. Changing the version to 3.9 makes it not work: NoClassDefFoundError on ConfigUtils, a newer aether-utils class.

Turns out that aether-utils 1.11 was being used, via dep from maven-core 3.0.3, whereas 1.13 was really needed for use from aether-connector-wagon. lib-jenkins-maven-embedder declared the correct versions in <dependencyManagement>, but since this is a jar project, that only affected its own version of Aether, not that of projects depending on it.

Suggested patch just makes these simple dependencies. Workaround from client of 3.9 is to explicitly request aether-spi and aether-util in 1.13, though there is still some problem with the version of AbstractHttpClientWagon I am trying to diagnose.