diff --git a/upgrade-mcp-release.groovy b/upgrade-mcp-release.groovy
index ad207cb..59659ab 100644
--- a/upgrade-mcp-release.groovy
+++ b/upgrade-mcp-release.groovy
@@ -110,7 +110,7 @@
                     // Do the same, for deprecated variable-duplicate
                     salt.cmdRun(venvPepper, 'I@salt:master', "cd /srv/salt/reclass/classes/cluster/$cluster_name && " +
                         "grep -r --exclude-dir=aptly -l 'apt_mk_version: .*' * | xargs --no-run-if-empty sed -i 's/apt_mk_version: .*/apt_mk_version: \"$targetMcpVersion\"/g'")
-                    salt.cmdRun(venvPepper, 'I@salt:master', "cd /srv/salt/reclass/classes/system && git checkout $gitTargetMcpVersion")
+                    salt.cmdRun(venvPepper, 'I@salt:master', "cd /srv/salt/reclass/classes/system && git checkout ${gitTargetMcpVersion}")
                     // Add new defaults
                     common.infoMsg("Add new defaults")
                     salt.cmdRun(venvPepper, 'I@salt:master', "grep '^- system.defaults\$' /srv/salt/reclass/classes/cluster/$cluster_name/infra/init.yml || " +