diff --git a/lib/simplepie/simplepie.inc b/lib/simplepie/simplepie.inc
index b87cbcd..4100354 100644
--- a/lib/simplepie/simplepie.inc
+++ b/lib/simplepie/simplepie.inc
@@ -11718,7 +11718,7 @@ class SimplePie_IRI
                }
                else
                {
-                       $this->query = $this->replace_invalid_with_pct_encoding($query, 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-._~!$\'()*+,;:@/?');
+                       $this->query = $this->replace_invalid_with_pct_encoding($query, 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-._~!$\'()*+,;=:@/?');
                }
                $this->valid[__FUNCTION__] = true;
                return true;