esawers: We had a Solution 660 panel, the installer kept all of the sensors and sirens and replaced the panel with a Solution 3000 (with ip panel?) so we can use the phone app to turn the alarm on and off. The app is very basic though

We had something done like that with an old Chubb alarm that used a key, and it got replaced with a Bosch system. The problem with the new systems when you get an installer in, is that they don't give you the installer codes, so you are locked out of all the  more advanced settings and configurations. They told me that if they give us that, they wouldn't provide any warranty with it and they would charge if there were any issues.  So we didn't bother  and just used the default settings. The company seems to have since disappeared. They really need to make these systems more user friendly IMO and provide more features to normal users without the installer codes.