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

# Versioning policy

> Protocol semver, version negotiation, and deprecation.

* The protocol uses **semver** (`MAJOR.MINOR.PATCH`). Wire-visible breaking changes bump MAJOR; additive capabilities bump MINOR. `[AWP-VER-001]`
* Agents send the list of protocol versions they support in `initialize`; the world MUST select the highest mutually supported version and echo it, or reject with `AWP_VERSION_UNSUPPORTED`. `[AWP-VER-002]`
* Unknown fields in any message MUST be ignored, never treated as errors (forward compatibility). `[AWP-VER-003]`
* Extension fields and modalities MUST use the `x-<vendor>.` prefix. `[AWP-VER-004]`
* Deprecated features remain functional for at least one MINOR release after the deprecation notice appears in the [changelog](/community/changelog). `[AWP-VER-005]`

## Wire version vs. artifact versions

The negotiated protocol version alone determines wire compatibility. Schema artifact releases and SDK package versions describe those artifacts — type organization, codegen structure, APIs — and MAY change without any wire change. Consumers MUST NOT infer wire compatibility from artifact versions. `[AWP-VER-006]`

## Capabilities gate optional features

Within a wire version, optional features are discovered through the `capabilities` maps exchanged in manifests — never by version sniffing. A feature's normative text names its gating capability key; absent the key, the feature's messages MUST be rejected as unknown. `[AWP-VER-007]`