Bridges will be used to relay communications between existing Zigbee and Z-Wave smart home networks, making them more like peripheral devices. While the details are to be worked out, there is a wide range of possibilities in which you get to keep your current setup and still use Matter devices.  It’s important to note that most of the engineering that goes into Matter technology is aimed at the application layer of the current IoT OSI models. Considering the data management capabilities of Matter, communicating with these devices should not be much of a problem. The Communications Standard Alliance ensures users on its website that it is still committed to Zigbee.