I have 1.20.01 and mine will lose dial tone and if you look at the device, line 1 and line 2 lights are out on the device. This happens every once and awhile. I have contacted support a few times about it, and have had no success with them.

Someone had suggested 1.25 or whatever was the newer version, but support did not want to update it.

I've pretty much given up on VoIPo support. I just reset the device when it happens.