I wish that SmartThings Developers would make the Home Monitor in the NEW app work like the Home Monitor in the OLD app.
The OLD app, if you have a Mode, such as Home Mode, when selected, or automatically switch to Home Mode by a automation, the OLD app would switch the Home Monitor to Disarmed. Same with a Vacation Mode, it would switch the Home Monitor to Arm (away). The NEW App does not do this.
Since the NEW app does not do this, the associated app, “Alarm for SmartThings” will not activate indicating Intrusion. In fact I get NO notification of Intrusion what so ever.
Therefore, I have to keep the OLD app installed on my phone just to preform this action. If SmartThings wants us all to use the NEW app, then they need to fix this.
Developers, PLEASE make the Home Monitor work like the OLD app Home Monitor !!
Unfortunately, it doesn’t look like they are going to make that change.
As you noticed, the new V3 app has a different design philosophy for security features than the classic V2 app had.
Specifically, you can no longer automate changing the security.mode or unlocking a Smart Lock. See the community FAQ:
FAQ: Why can’t I use Geopresence or an Automation to set the alarm state in the new (V3) app? (also applies to unlocking smart locks)
But feel free to use one of the official channels like the Twitter feed or the Facebook page to tell them that you would like to have this choice again. Because right now it sucks.
Also, be aware that smart home monitor in the V2 classic app and the SmartThings home monitor in the new V3 apps are completely independent features using different code. So if you set up an automation in one of these apps you will not be able to dismiss it from the other one.
I would recommend writing to ST support. If enough users ask for it, they may implement a way to do it.