diff --git a/lib/filteringnoticestream.php b/lib/filteringnoticestream.php
index 96b9432fc1..f412211074 100644
--- a/lib/filteringnoticestream.php
+++ b/lib/filteringnoticestream.php
@@ -56,7 +56,7 @@ abstract class FilteringNoticeStream extends NoticeStream
 
     abstract function filter($notice);
 
-    function getNotices($offset, $limit, $sinceId, $maxId)
+    function getNotices($offset, $limit, $sinceId=null, $maxId=null)
     {
         // "offset" is virtual; we have to get a lot
         $total = $offset + $limit;
diff --git a/lib/noticestream.php b/lib/noticestream.php
index 025138be4d..be28aa6186 100644
--- a/lib/noticestream.php
+++ b/lib/noticestream.php
@@ -48,7 +48,7 @@ abstract class NoticeStream
 {
     abstract function getNoticeIds($offset, $limit, $since_id, $max_id);
 
-    function getNotices($offset, $limit, $sinceId, $maxId)
+    function getNotices($offset, $limit, $sinceId = null, $maxId = null)
     {
         $ids = $this->getNoticeIds($offset, $limit, $sinceId, $maxId);