Thanks for your post and apologies to hear the Pod is no longer connecting to the Hub.
The Pod will work with the Hub 3 or your new Hub 4, it will just need to connect to it.
There are a few requirements for the Pods to work with our Hubs so double check the following on your new Hub: .
The Hub must be in 'Router Mode' and not have been changed to 'Modem Mode'
Channel Optimisation must be left on
The SSIDs must be the same and broadcast enabled
The Passphrases of the SSIDs must match
As long as all of the above points are all met then the Pods will automatically connect to your Hub's WiFi and begin broadcasting. The wireless details from the Pods will be the same as the Hub's details, so no additional steps are required to connect up the devices in the home.