diff --git a/CHANGELOG b/CHANGELOG
index 7c7c673..b5e231b 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -1,6 +1,11 @@
 CHANGELOG
 =========
 
+0.5.1
+-----
+
+* Fix accidental merge with SNAPSHOT version in to master
+
 0.5.0
 -----
 
diff --git a/Jenkinsfile.groovy b/Jenkinsfile.groovy
index 3f87b24..b9d862b 100644
--- a/Jenkinsfile.groovy
+++ b/Jenkinsfile.groovy
@@ -9,6 +9,18 @@ pipeline {
                 git url: gitRepoUrl, branch: '**', credentialsId: 'github-kemitix'
             }
         }
+        stage('no SNAPSHOT in master') {
+            // checks that the pom version is not a snapshot when the current branch is master
+            // TODO: also check for SNAPSHOT when is a pull request with master as the target branch
+            when {
+                expression {
+                    (env.GIT_BRANCH == 'master') &&
+                            (readMavenPom(file: 'pom.xml').version).contains("SNAPSHOT") }
+            }
+            steps {
+                error("Build failed because SNAPSHOT version")
+            }
+        }
         stage('Build') {
             parallel {
                 stage('Java 8') {
diff --git a/pom.xml b/pom.xml
index 7febbd4..92dfb5e 100644
--- a/pom.xml
+++ b/pom.xml
@@ -11,7 +11,7 @@
         <relativePath/>
     </parent>
     <artifactId>mon</artifactId>
-    <version>0.6.0-SNAPSHOT</version>
+    <version>0.5.1</version>
 
     <properties>
         <java.version>1.8</java.version>