Sentry is deprecating its U2F API for registration and authentication, replacing it with WebAuthn due to Google Chrome's decision to stop supporting U2F API after February 2022. The migration process involves two main parts: authenticating existing devices using WebAuthn and registering new devices. To migrate, developers must replace deprecated APIs with their WebAuthn counterparts and update their authentication flow to use the new specification. WebAuthn is an API that allows web services to seamlessly integrate strong authentication into applications, providing users with a choice of authenticators such as security keys or built-in platform authenticators.