Questions on Firmware Update for Temperature Sensors

Hello,

When I open a webpage to connect to my sensor it shows

Hardware VersionRelease 5.1
Firmware VersionRelease 8.10 (Jul 1 2019)

The problem is on the webpage I cannot see any information on what model these sensors are. But they appear to be very old.

Looking at this page all models are discontinued except for the V5 model. All the older models the firmware version is very old if I click on the V4 model the firmware download shows v2.11.

How can I determine what model my sensor is the only way to upgrade the firmware to purchase new temperature sensors?

It depends when you purchased your unit if its 5 years back or more you may have to update it if you would buy new sensors, also why would you need a firmware upgrade usually it is only when you purchase new sensors that you'd need it.