We used to link our instance of Discourse with a database of members stored on our server. Users would log in through SSO and their account details would be synced to Discourse.
We’ve since migrated to using NeonCRM to manage our members and will be using OAuth2 to have them sign in using their NeonCRM credentials. We are in the process of getting our Discourse forum back up but I’m wondering how old users in Discourse (which were restored from our last backup) will be treated by the system once they sign in through OAuth2. Will the account link up? And if they do, is it based on the email address? If the email address has since then changed, I assume a new user will be created in Discourse?