You can fix the version mismatch by upgrading your client-side library. It's generally best to be running the same version of the library both client and server side. That being said, things will work fine, unless you are trying to use a device or API which requires the newer version.
I'm seeing lots of IO errors. This indicates that the network connection is not stable. Whether this is an issue with the HUB5000s, the WiFi AP, or the PC, is really hard to say. When the server sees an interruption in the connection, it closes and resets any open channels. The client side will keep trying to reconnect. Are you able to connect a HUB5000 via ethernet, without changing anything else, and see if that's more stable? Out of the 5 VINT hubs, are you seeing issue with all of them?