Fix regression Date Backup

core/class/core.class.php

@@ -109,6 +109,15 @@ class core
         }
     }
 
+    public static function dateFromTimestamp(int $_timestamp = NULL)
+    {
+        if ($_timestamp == NULL) { 
+            return NULL;
+        } else {
+            return date("Y-m-d H:i:s", $_timestamp);
+        }
+    }
+
     public static function dateWhithoutHours(string $_datetime)
     {
         return explode(" ", $_datetime)[0];