I have about 10 of the original switches purchased about 5 years ago. I got them when I was using the Vera Lite hub.
They seem to stay connected for about a day and then do not respond to commands or update status.
I have ran repair network several times and I get lots of can not update routes or mesh info.
This problem has pretty much crashed my Z-Wave network.
My ST v2 hub has 17.11 on it.