The Auth extension was previously called Members. If you used members you will need to migrate database tables, config files, twig functions and any php use of events/namespaces to the new name.
Database
To rename the database tables run the following:
MySQL
ALTER TABLE `bolt_members_account` RENAME TO `bolt_auth_account` ;
ALTER TABLE `bolt_members_account_meta` RENAME TO `bolt_auth_account_meta` ;
ALTER TABLE `bolt_members_oauth` RENAME TO `bolt_auth_oauth` ;
ALTER TABLE `bolt_members_provider` RENAME TO `bolt_auth_provider` ;
ALTER TABLE `bolt_members_token` RENAME TO `bolt_auth_token` ;
PostgreSQL
ALTER TABLE bolt_members_account RENAME TO bolt_auth_account;
ALTER TABLE bolt_members_account_meta RENAME TO bolt_auth_account_meta;
ALTER TABLE bolt_members_oauth RENAME TO bolt_auth_oauth;
ALTER TABLE bolt_members_provider RENAME TO bolt_auth_provider;
ALTER TABLE bolt_members_token RENAME TO bolt_auth_token;
ALTER SEQUENCE bolt_members_account_id_seq RENAME TO bolt_auth_account_id_seq;
ALTER SEQUENCE bolt_members_account_meta_id_seq RENAME TO bolt_auth_account_meta_id_seq;
ALTER SEQUENCE bolt_members_oauth_id_seq RENAME TO bolt_auth_oauth_id_seq;
ALTER SEQUENCE bolt_members_provider_id_seq RENAME TO bolt_auth_provider_id_seq;
ALTER SEQUENCE bolt_members_token_id_seq RENAME TO bolt_auth_token_id_seq;
SQLite
Not tried yet, but should be the same as MySQL. Let me know if you tried it!
Config file
The Members config file was called members.bolt.yml. Rename that file to auth.boltauth.yml.
Twig functions
Any twig functions that were called anything with member should be renamed to
the equivalent with auth. For example is_member() is now is_auth()`.
PHP usage
Any other extensions that used the old name will need to be updated. As an example you can look at this commit in AuthFields or this commit in the Bolt market