> ## Documentation Index
> Fetch the complete documentation index at: https://sendmux.ai/docs/llms.txt
> Use this file to discover all available pages before exploring further.

# Versioning and support

> Understand Sendmux SDK package releases, compatibility, and support expectations.

SDK packages track the public Sendmux API contracts. A package update can be limited to one language or one surface when the change only affects that package.

## Versioning model

* Current SDK packages are in the `1.x` release line.
* Patch versions can differ between packages.
* Generated clients are built from the same public API contracts used by the API reference.
* API contract changes update the relevant SDK output in the same package release.
* Pin the major version your application is tested against. Review package release notes before upgrading.

## Compatibility checks

Check the package registry for the version you install, then compare the package surface with the API reference:

* Use the [Sending API](/docs/sending-api/introduction) for outbound email behaviour.
* Use the [Mailbox API](/docs/mailbox-api/introduction) for mailbox and message behaviour.
* Use the [Management API](/docs/api/introduction) for team-level resources.
* Use [API keys](/docs/guides/api-keys) to confirm the key scope before testing.

## Support requests

For SDK help, include:

* Package name and version.
* Language runtime and operating system.
* Command, import path, or client method involved.
* The API surface: Sending, Mailbox, or Management.
* Sanitised request or response details.
* `X-Request-Id` or `meta.request_id` from an API response, if present.

Do not include API keys, passwords, tokens, webhook secrets, customer data, or private account details.

## Security reports

Report suspected vulnerabilities privately through [contact@sendmux.ai](mailto:contact@sendmux.ai). Do not open a public GitHub issue for security reports.

## Next steps

<CardGroup cols={2}>
  <Card title="SDK overview" icon="code" href="/docs/sdks">
    Choose an SDK package and API surface.
  </Card>

  <Card title="Errors" icon="shield-check" href="/docs/api/errors">
    Review the shared API error envelope and retry guidance.
  </Card>

  <Card title="Idempotency" icon="rotate" href="/docs/guides/idempotency">
    Make retries safe for mutating API requests.
  </Card>

  <Card title="Support" icon="envelope" href="mailto:contact@sendmux.ai">
    Contact Sendmux for account-specific support.
  </Card>
</CardGroup>