Are there other probe styles available for this data logger? What is the probe type (previous versions used a k-type probe)?

This logger comes with a thermistor type probe. It is not compatible with any other types of sensors. The Type K probe you are talking about is what comes with the EL-USB-TC-LCD which is a thermocouple data logger. That is compatible with any thermocouple probes using a mini connector. That logger still ships with a Type K probe.