This module is found in the module tab, in the OPC Connector program. At the moment this module is only supported by Process values. It is activated via a check box called "Send to web socket" via "Client" -> "Administration" -> "System settings" -> "Process values" -> "Miscellaneous" -> "Send to web sockets". Here is more information on how that section works. Please note that this requires version 23.4.0, or higher to work.
From this version the system supports SignalR based web sockets. This is used to reduce the amount of time it takes from when a process value is changed in the system, to when that change of the process value is seen in the web application BZX21.