diff --git a/ocs/v1.php b/ocs/v1.php
index 398a128c64be69651ff772485e73217728f7adaf..8002ca602e6880e11128e3090e5b7d6f402b6f73 100644
--- a/ocs/v1.php
+++ b/ocs/v1.php
@@ -27,7 +27,9 @@
 
 require_once '../lib/base.php';
 
-if (\OCP\Util::needUpgrade() || \OC::$server->getSystemConfig()->getValue('maintenance', false)) {
+if (\OCP\Util::needUpgrade()
+	|| \OC::$server->getSystemConfig()->getValue('maintenance', false)
+	|| \OC::$server->getSystemConfig()->getValue('singleuser', false)) {
 	// since the behavior of apps or remotes are unpredictable during
 	// an upgrade, return a 503 directly
 	OC_Response::setStatus(OC_Response::STATUS_SERVICE_UNAVAILABLE);