Teleport client server version compatibility

Teleport tsh and tctl client compatibility after server major version upgrade

0 reputation · 29 May 2025, 05:28 UTC

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Teleport ships the tsh and tctl clients separately from the cluster server, and upgrade guidance begins with auth_service before proxy and node services. The goal is to determine whether a client on an older major version can still authenticate after the server has moved forward, or whether protocol negotiation fails before authentication is evaluated.

Release notes describe breaking changes per version rather than a single client-to-server compatibility matrix. Because a version mismatch can surface as an authentication error, it is unclear whether the proxy returns a version-specific rejection or an opaque login failure during a mixed-major-version transition. Confirming this against the target release notes is needed before relying on older client binaries.

Does Teleport reject tsh or tctl connections when the client major version differs from the auth service? What error distinguishes a protocol version mismatch from a credential failure? Is matching major-version support required for WebAuthn and OIDC device-code login after the proxy is upgraded?

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Key Points

When a Teleport cluster moves from one major release to the next (e.g., 14.x → 15.x), the authentication protocol envelope changes. A tsh or tctl binary that is one major version behind will be rejected by the proxy with a clear version-specific error:

ERROR: client version too old – server requires 15.x or newer

Credential failures, such as wrong password or missing MFA, still produce the usual invalid credentials message. Because WebAuthn and OIDC device-code flows rely on the protocol handshake, an older client will fail to initiate the flow, often surfacing as a generic "authentication failed" error that masks the underlying version mismatch.

Best practice is to upgrade tsh and tctl to the same major version as the server before resuming interactive logins. Check the release notes for the target server version for any "client version" or "protocol change" entries.

Teleport tsh and tctl client compatibility after server major version upgrade

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Key Points