SensorProbeIO - usage for new sensors

In, I found:
Two ways to work with 3rd party sensors:

  1. Pre-attached sensors
    RAK integrates some industrial sensors that are widely used in the market through the Probe IO sensor data interface.
  2. User-selected sensors
    The Probe IO also allows users to connect their own sensors through the terminal block.

The first is clear to me, and I tested with success the weather station.
For user-selected sensors the electrical conditions are clear. I can connect the wires of the Sensor via the terminal block. But what about the firmware? Does it mean I must program a customized firmware, or is it possible to configure the SensorHub firmware anyway? It seems, for example, that Modbus RTU is implemented. Can I use it for another sensor with Modbus RTU/RS485 interface, too?