diff --git a/application/MaintenanceNotification/MaintenanceNotification.php b/application/MaintenanceNotification/MaintenanceNotification.php
index 6bff72170..195b91839 100644
--- a/application/MaintenanceNotification/MaintenanceNotification.php
+++ b/application/MaintenanceNotification/MaintenanceNotification.php
@@ -407,10 +407,17 @@ class MaintenanceNotification extends mfBaseModel {
         if(array_key_exists("to>", $filter)) {
             $to = $filter['to>'];
             if(is_numeric($to)) {
-                $where .= " AND MaintenanceNotification.to >= $to";
+                $where .= " AND MaintenanceNotification.to > $to";
             }
         }
 
+        if(array_key_exists("send_ts<", $filter)) {
+            $send_ts = $filter['send_ts<'];
+            if(is_numeric($send_ts)) {
+                $where .= " AND MaintenanceNotification.send_ts <= $send_ts";
+            }
+        }
+        
         if(array_key_exists("sent", $filter)) {
             $sent = $filter['sent'];
             if($sent === true) {
diff --git a/application/MaintenanceNotification/MaintenanceNotificationController.php b/application/MaintenanceNotification/MaintenanceNotificationController.php
index ca5d220b0..39ae1e332 100644
--- a/application/MaintenanceNotification/MaintenanceNotificationController.php
+++ b/application/MaintenanceNotification/MaintenanceNotificationController.php
@@ -138,18 +138,21 @@ class MaintenanceNotificationController extends mfBaseController {
         $data["to"] = $to->getTimestamp();
 
 
-        try {
-            $send_ts = new DateTime($r->sendts_day." ".$r->sendts_hour.":00");
-            //var_dump($send_ts);exit;
-        } catch(Exception $e) {
-            $this->layout()->setFlash("Ungültige Versandzeitpunkt", "error");
-            if($mode = "edit") {
-                return $this->editAction();
+        if($r->sendts_day && $r->sendts_hour) {
+            try {
+                $send_ts = new DateTime($r->sendts_day . " " . $r->sendts_hour . ":00");
+                //var_dump($send_ts);exit;
+            } catch(Exception $e) {
+                $this->layout()->setFlash("Ungültige Versandzeitpunkt", "error");
+                if($mode = "edit") {
+                    return $this->editAction();
+                }
+                return $this->addAction();
             }
-            return $this->addAction();
+            $data["send_ts"] = $send_ts->getTimestamp();
+        } else {
+            $data["send_ts"] = null;
         }
-        $data["send_ts"] = $send_ts->getTimestamp();
-
 
         if($mode == "add") {
             $notification = MaintenanceNotification::create($data);
diff --git a/scripts/send-maintenance-notifications.php b/scripts/send-maintenance-notifications.php
index 4c3a05dd7..ea937b6cd 100755
--- a/scripts/send-maintenance-notifications.php
+++ b/scripts/send-maintenance-notifications.php
@@ -16,6 +16,6 @@ define("INTERNAL_USER_ID", $me->id);
 define("INTERNAL_USER_USERNAME", $me->username);
 define("MFBASE_BYPASS_LOGIN", true);
 
-foreach(MaintenanceNotification::searchActive([]) as $notification) {
+foreach(MaintenanceNotification::searchActive(["send_ts<" => date("U")]) as $notification) {
     $notification->sendToRecipients();
 }