Requirements:
A) Any pom.xml file in droolsjbpm should not declare <version>, except for kie-dependency-with-dependencies. This way, all droolsjbpm modules work with the same version of a dependency and are certain to be compatible.
B) All dependencies that are also a dependency of EAP must use the same version EAP.

jbpm-form-modeler, specifically the module jbpm-form-modeler-common and jbpm-form-modeler-renderer, doesn't adhere to these requirements yet.

Recommended steps for jbpm-designer-backend:
1) Remove all dead dependencies first
2) Make a list of all dependencies that are not yet specified in kie-dependency-with-dependencies. Add them to kie-dependency-with-dependencies.
3) Compare that list with EAP's dependencies. If EAP uses a different version, specify the EAP version in kie-dependency-with-dependencies.

Related issue:
jbpm-form-modeler-renderer uses commons-logging - that should be replaced by slf4j and logback like the rest of droolsjbpm.