diff --git a/vars/drafter.groovy b/vars/drafter.groovy
index aa8838a..4769a55 100644
--- a/vars/drafter.groovy
+++ b/vars/drafter.groovy
@@ -56,7 +56,7 @@
 def queryDraftset(String baseUrl, String credentials, String id, String query, String type) {
     echo "Querying draftset ${id}"
     String sparqlQuery = java.net.URLEncoder.encode(query, "UTF-8")
-    def response = httpRequest(acceptType: type,
+    def response = httpRequest(customHeaders: [[name: 'Accept', value: type]],
             authentication: credentials,
             httpMode: 'POST',
             url: "${baseUrl}/v1/draftsets?id=${id}&query=${sparqlQuery}&union-with-live=true")