diff --git a/lib/SimpleSAML/Metadata/SAMLBuilder.php b/lib/SimpleSAML/Metadata/SAMLBuilder.php
index edd176e52762a2d6fcf8402d5001435ee2f16ed5..9dcfcbfd23c9c20677de39e0181b3986bf42c969 100644
--- a/lib/SimpleSAML/Metadata/SAMLBuilder.php
+++ b/lib/SimpleSAML/Metadata/SAMLBuilder.php
@@ -438,6 +438,7 @@ class SimpleSAML_Metadata_SAMLBuilder {
 
 		$e = new SAML2_XML_md_IDPSSODescriptor();
 		$e->protocolSupportEnumeration[] = 'urn:oasis:names:tc:SAML:1.1:protocol';
+		$e->protocolSupportEnumeration[] = 'urn:mace:shibboleth:1.0';
 
 		$this->addCertificate($e, $metadata);