- `alpha` support (guarded by the `ServiceAccountTokenJTI` feature gate) for adding a `jti` (JWT ID) claim to service account tokens it issues, adding an `authentication.kubernetes.io/credential-id` audit annotation in audit logs when the tokens are issued, and `authentication.kubernetes.io/credential-id` entry in the extra user info when the token is used to authenticate.

* **[alpha]** New Bootstrap Token authentication and management method. Works well with kubeadm. kubeadm now supports managing tokens, including time based expiration, after the cluster is launched.  See [kubeadm reference docs](https://kubernetes.io/docs/admin/kubeadm/#manage-tokens) for details.

 * kubeadm: The Token-related fields in the `MasterConfiguration` object have now been refactored. Instead of the top-level `.Token`, `.TokenTTL`, `.TokenUsages`, `.TokenGroups` fields, there is now a `BootstrapTokens` slice of `BootstrapToken` objects that support the same features under the `.Token`, `.TTL`, `.Usages`, `.Groups` fields. ([#64408](https://github.com/kubernetes/kubernetes/pull/64408), [@lu...

enabled by default. When enabled, Secret API objects containing service account tokens are no longer auto-generated for every ServiceAccount. Use the [TokenRequest](https://kubernetes.io/docs/reference/kubernetes-api/authentication-resources/token-request-v1/) API to acquire service account tokens, or if a non-expiring token is required, create a Secret API object for the token controller to populate with a service account token by following this [guide](https://kubernetes.io/docs/concepts/configurati...

  - This changes the tokens provided to containers at `/var/run/secrets/kubernetes.io/serviceaccount/token` to be time-limited, auto-refreshed, and invalidated when the containing pod is deleted.
  - Clients should reload the token from disk periodically (once per minute is recommended) to ensure they continue to use a valid token. `k8s.io/client-go` version v11.0.0+ and v0.15.0+ reload tokens automatically.

- Promoted the `ServiceAccountTokenJTI` feature to GA, which adds a `jti` claim to issued service account tokens and embeds the `jti` claim as a `authentication.kubernetes.io/credential-id=["JTI=..."]` value in user extra info

- Kube-apiserver can now specify `--authentication-token-webhook-version=v1` or `--authorization-webhook-version=v1` to use `v1` TokenReview and SubjectAccessReview API objects when communicating with authentication and authorization webhooks. ([#84768](https://github.com/kubernetes/kubernetes/pull/84768), [@liggitt](https://github.com/liggitt))

    * kube-apiserver: the OpenID Connect authenticator no longer accepts tokens from the Google v3 token APIs, users must switch to the "https://www.googleapis.com/oauth2/v4/token" endpoint.

- The alpha feature `ServiceAccountIssuerDiscovery` enables publishing OIDC discovery information and service account token verification keys at `/.well-known/openid-configuration` and `/openid/v1/jwks` endpoints by API servers configured to issue service account tokens. ([#80724](https://github.com/kubernetes/kubernetes/pull/80724), [@cceckman](https://github.com/cceckman)) [SIG API Machinery, Auth, Cluster Lifecycle and Testing]

</p>

<h3 id="Tokens">Tokens</h3>

<p>
Tokens form the vocabulary of the Go language.
There are four classes: <i>identifiers</i>, <i>keywords</i>, <i>operators
and punctuation</i>, and <i>literals</i>.  <i>White space</i>, formed from
spaces (U+0020), horizontal tabs (U+0009),
carriage returns (U+000D), and newlines (U+000A),
is ignored except as it separates tokens