diff --git a/buildtree/buildtree.go b/buildtree/buildtree.go
index 2371143..6c49654 100644
--- a/buildtree/buildtree.go
+++ b/buildtree/buildtree.go
@@ -115,6 +115,7 @@ func readBuildConfig(fileContent []byte, variableMap map[string]string) (*config
 	if err != nil {
 		return nil, err
 	}
+	tmpl = tmpl.Option("missingkey=error")
 	b := &bytes.Buffer{}
 	err = tmpl.Execute(b, variableMap)
 	if err != nil {
diff --git a/utils/common.go b/utils/common.go
index 468b572..7bed67d 100644
--- a/utils/common.go
+++ b/utils/common.go
@@ -11,7 +11,7 @@ import (
 
 // Version returns doriath version
 func Version() string {
-	return "1.3.0"
+	return "1.3.1"
 }
 
 // ResolveDir appends a path to a rootDir