They haven't improved at all. It is the same device.
The battery life is pretty poor too as I discovered since I originally posted my comment. I reckon they all needed batteries within 6 weeks, (I bought ten of the things)
They also stop working for reasons other than the battery going flat. I think this may be damage ( on a key ring ) or water, sweat or general poxy build quality. None of the ten I bought now work even with new batteries.
They have agreed to take them all back but I can only find five of them.
They will not help you find a stolen bike. Not in a million years.