Retrofit security system using Z-Wave

I have an old security system that uses six normally closed dry contact inputs.
I’d like to rewire the old connections into a Z-Wave board that would send open/closed status to indigo.
I understand Ring makes a retrofit kit but all of their “features” require a monthly subscription. No thanks.
I just want the new board to talk to indigo… and have indigo do what it does (everything!!!
Any recommendations?

Get one of these and then use MQTT to communicate with it?

https://konnected.io