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

# Versioning

> How ACK protocol versions are managed and identified.

The Agent Commerce Kit (ACK) specifications as a whole use string-based version identifiers following the format `YYYY-MM-DD`. This date indicates when the last set of backwards-incompatible changes were introduced to the core protocols (ACK-ID or ACK-Pay).

<Info>
  The protocol version identifier will typically *not* change when updates are
  made that maintain backwards compatibility (e.g., adding optional parameters,
  clarifying existing behavior). This allows for incremental improvements while
  preserving interoperability with implementations based on the same or earlier
  compatible versions within a dated release.
</Info>

## Revisions

Specific documentation versions or implementations might be marked as:

* **Draft**: In-progress specifications or features, not yet stable or recommended for production use.
* **Current**: The latest stable protocol version, ready for use and potentially receiving ongoing backwards-compatible updates under the same date identifier.
* **Final/Legacy**: Past, complete specifications identified by their date, which will not receive further changes. New development should target the "Current" version.

The **current** stable protocol version is **2025-05-04**.

*(Note: Specific implementation libraries or SDKs built upon ACK may follow their own versioning schemes, like Semantic Versioning, but should clearly state which ACK protocol version `YYYY-MM-DD` they are compatible with.)*