Envisalink question

Greetings. Not to revive an old thread, but new comer here, and got few basic questions.

My house too came equipped with an ADT SafeWatch Pro 300 (Photos Below). The system is hard-wired to multiple contact switches (doors/windows) and PIR motion sensors in some areas. I’d like to possibly re-use many of the sensors. Thus my questions/comments

  1. Can I build upon the existing system, or completely remove it?
  2. What options are out there for a new panel/upgrade. I’m sure the various sensors can stay.
  3. I’ve checked with ADT, they have very ‘blown-up’ solutions and not interested in those, at least not for now.
  4. At the very least, would like to have status/reporting on the various doors/windows switches and PIRs (Presence/Occupancy).
  5. The system is about 15-18 years old - Throw it out and start new ?

Appreciate any answers/leads.

ADT_Panel