2476ST is a power line only module. A restore as mentioned may do it for you.
Locally does the LED bar graph move up and down when the paddle is uses?
A factory reset and restore sometimes helps, but depending on its revision. May not have an Air Gap switch used in a factory reset. There is a method for the old ones. I have it if you need it. The information is on the sticker on the front of it.
You asked about last firmware version for the 2476ST. It is 5.3.4. Though if everything is OK now you may want to hold off on the upgrade for now.