echo $sql='UPDATE '.$tbl_message.' SET msg_status='.MESSAGE_STATUS_INVITATION_ACCEPTED.' WHERE user_sender_id='.((int)$user_send_id).' AND user_receiver_id='.((int)$user_receiver_id).';';
$sql='UPDATE '.$tbl_message.' SET msg_status='.MESSAGE_STATUS_INVITATION_ACCEPTED.' WHERE user_sender_id='.((int)$user_send_id).' AND user_receiver_id='.((int)$user_receiver_id).';';