Free SmartThings V2 (2015) Hub

You can reach out to ST support. Hopefully they will be able to give you a definitive answer. But we have seen this before and always the same ending. There is no avenue for the hub to communicate with ST to update to a working hub.

here is the same issue in May: https://community.smartthings.com/t/help-with-setup-smartthings-v2/281707/16