right now, there only appears to be Used Aeotec hubs for Sale –> https://smartmatters.co/collections/zigbee-hubs-gateways/products/aeotec-smart-home-hub-smartthings-aeohubv3
There are indications that a new V4 hub may be released at the end of August or early September but nothing has been confirmed except it appears to have shown up in South Korea. https://community.smartthings.com/t/new-smartthings-v4-hub-released-do-you-already-know-about-it/303946/