Supporting Google Account username change in your app

In March, Google announced that US users can now update their Google Account usernames while retaining their account, inbox, and data intact, with both the old and new email addresses remaining active and pointing to the same inbox. This update, previously available to business Workspace users, is now extended to consumer Google Accounts with an @gmail.com address. For platforms using Sign in with Google, the impact varies based on user authentication methods; those using subject ID as the primary identifier need no changes, while platforms using email addresses might face issues like duplicate accounts. To ensure continuity, Google recommends adopting subject ID as the primary user identifier, enabling email updates on platforms, and offering email-based account recovery. These measures aim to enhance user experience by providing a seamless transition and maintaining access continuity.