diff --git a/Jenkinsfile b/Jenkinsfile
index ee9203e..af1fe42 100644
--- a/Jenkinsfile
+++ b/Jenkinsfile
@@ -128,6 +128,11 @@ def build_version(versionParam) {
     String newVersionStr = versionParam 
     versionArr[0] = newVersionStr
   }
+  else {
+    def buildnbr = getTopUpstreamBuildNumber()
+    String nightlyPart = versionArr[0] + ".Test${buildnbr}"
+    versionArr[0] = nightlyPart
+  }
   rlsVersion = versionArr.join("-")
   return rlsVersion
 }
@@ -226,4 +231,18 @@ def archive(image_type_in, single_fitImage) {
   }
 }
 
-
+def getTopUpstreamBuildNumber() {
+  // Iterating though all upstream jobs:
+  //   currentBuild.upstreamBuilds.each { item ->
+  //     echo "upstream build: ${item}"
+  //     def nbr = item.getNumber()
+  //     echo "nbr=${nbr}"
+  //   }
+  def upstreamJobList = currentBuild.upstreamBuilds
+  def nbrOfUpstreamJobs = upstreamJobList.size()
+  def topJob = upstreamJobList[nbrOfUpstreamJobs-1]
+  println "Top upstream project: " + topJob.getFullDisplayName()
+  def topJobNbr = topJob.getNumber()
+  println "Top upstream job build Number = ${topJobNbr}"
+  return topJobNbr
+}