diff --git a/Jenkinsfile b/Jenkinsfile
index e859610..3084d5c 100644
--- a/Jenkinsfile
+++ b/Jenkinsfile
@@ -43,7 +43,7 @@ pipeline {
     }
 
     stage('Publish Devel') {
-      when { expression { env.GIT_BRANCH !=~ /.*master/ } }
+      when { expression { !(env.GIT_BRANCH ==~ /.*master/) } }
       steps {
         sshagent(credentials: ['jenkins-ssh']) {
           sh """