jenkins-getUpstreamJobParameters.groovy

    for (cause in currentBuild.rawBuild.getCauses()) {
        if (cause instanceof Cause.UpstreamCause) {
            def upstreamProjectName = cause.getUpstreamProject()
            echo upstreamProjectName
            def job = hudson.model.Hudson.instance.getItem(upstreamProjectName)
            def build = job.getBuildByNumber(cause.getUpstreamBuild())
            echo build.buildVariableResolver.resolve("version")
        }
    }