Curtelec is a software to monitor power alimentation and can send an alert on power change. So you can use a phone/tablet to monitor power shutdown at your home, office... at any time and any place. Each power status can be associated with varied actions. Google Play Store version can't send SMS. If you're using this software on a machine that isn't regularly checked, it's advisable to disable automatic updating, so as not to interrupt monitoring when updates are made.
Due to battery management, some phone brands does not work well. Huawei: not working, app is closed after some hours/days. Samsung: works OK on old or new devices.