diff --git a/kea_testing.groovy b/kea_testing.groovy
index 0d556d2..b4d78a6 100644
--- a/kea_testing.groovy
+++ b/kea_testing.groovy
@@ -111,7 +111,7 @@ pipeline {
             }
             testName = "KEA_F004"
             url = "mqtt://${HOST_IP}:1883/test"
-            responseCode = sh(label: testName, script: "sleep 2 ; curl -d 1 $url & OUT=$( curl -m 4 -s $url ) ; echo $OUT", returnStdout: true)
+            responseCode = sh(label: testName, script: "sleep 2 ; curl -d 1 $url & OUT=`curl -m 4 -s $url` ; echo $OUT", returnStdout: true)
             if (responseCode != 'test1') {
               error("$testName: Returned status code = $responseCode when calling $url")
             }