I can not find where in your program I can turn on the notification that the client is offline by SMS or by e-mail. Where it is configured, if it is not there then your program has one big minus. When my computer goes offline I do not receive SMS notifications and 2 notifications via e-mail. Why you did not do it I do not understand. After all, now all services are able to send sms or push notification. I'm not talking about e-mail .... messages that your remote computer offline should be sent by default instantly.