diff --git a/lib/activityutils.php b/lib/activityutils.php
index 4f31648ead..58e04e2f76 100644
--- a/lib/activityutils.php
+++ b/lib/activityutils.php
@@ -294,7 +294,7 @@ class ActivityUtils
         // Possibly an upstream bug; tag: URIs aren't validated properly
         // unless you explicitly ask for them. All other schemes are accepted
         // for basic URI validation without asking.
-        if ($validate->uri($uri, array('allowed_scheme' => array('tag')))) {
+        if ($validate->uri($uri, array('allowed_schemes' => array('tag')))) {
             return true;
         }