SmartApp just disappeared from ST

I’ve installed a custom “5-2 Thermostat schedule” application and it’s been working fine until yesterday when it simply vanished from my device. Is there a way to find out what happened? I hate to have to enter all the settings again knowing it’s not going to stay

/rant on
Also (and I know it’s wrong to raise multiple topics in one post) the absence of a “Just schedule” application in ST is mind-boggling. Looks like nobody ever heard of ADT schedule (I agree, ADT is evil but they got schedule right). Why do I need to have multiple “schedule this” and “schedule that” applications instead of just one? Try to configure 2 thermostats each on different schedule, you’ll see what I’m talking about
/rant off