How to get a project's ivy version?

The answer of HaraldWeber is basically good. The version of the current trunk is wrong yet, it will set just before the release. It's to be decided which will be the final version number (5.2 or 6.0)

tip: you may navigate from iProject to ivyProject also: ivyProject= (IIvyProject) pmv.getProject().getAdapter(IIvyProject.class); versionNumber = ivyProject.getVersion()

So the 2 first digits of the Engine (e.g. "6.0" -> "60" ) should be greater or equal to the first 2 digits of the project version number. (e.g. 51902 -> "51") then your Engine is not older than the project.

In fact the engine contains some other validators which help to prove if a project is acceptable to be deployed or not. (e.g. Java classes are built)

This should do it.

IProject project = WorkflowNavigationUtil
  .getWorkflowProcessModelVersion(
    Ivy.request().getProcessModelVersion())
      .getProject();
IIvyProject ivyProject = IvyProjectUtil
  .getIvyProjectByName(project.getName());
Ivy.log().info(ivyProject.getVersion());