Deprecation notices landed; older articles kept their old promises.
Zendesk announced three auth and data changes this year: password access to the API ended Jan 12, API tokens are being phased out starting July 28, and legacy custom objects began removal July 27. The announcement pages are current. Several older how-to articles are not. The admin guide for legacy custom objects still tells readers they will keep access, and the API authentication article still lists email and password as a valid method.
See evidence in the table