diff --git a/phpBB/memberlist.php b/phpBB/memberlist.php
index a0e7d91875..b5eb3312dd 100644
--- a/phpBB/memberlist.php
+++ b/phpBB/memberlist.php
@@ -1079,14 +1079,9 @@ switch ($mode)
 
 			if (isset($find_key_match[$joined_select]) && sizeof($joined) == 3)
 			{
-				// Before PHP 5.1 an error value -1 can be returned instead of false.
-				// Theoretically gmmktime() can also legitimately return -1 as an actual timestamp.
-				// But since we do not pass the $second parameter to gmmktime(),
-				// an actual unix timestamp -1 cannot be returned in this case.
-				// Thus we can check whether it is -1 and treat -1 as an error.
 				$joined_time = gmmktime(0, 0, 0, (int) $joined[1], (int) $joined[2], (int) $joined[0]);
 
-				if ($joined_time !== false && $joined_time !== -1)
+				if ($joined_time !== false)
 				{
 					$sql_where .= " AND u.user_regdate " . $find_key_match[$joined_select] . ' ' . $joined_time;
 				}
@@ -1096,7 +1091,7 @@ switch ($mode)
 			{
 				$active_time = gmmktime(0, 0, 0, (int) $active[1], (int) $active[2], (int) $active[0]);
 
-				if ($active_time !== false && $active_time !== -1)
+				if ($active_time !== false)
 				{
 					$sql_where .= " AND u.user_lastvisit " . $find_key_match[$active_select] . ' ' . $active_time;
 				}