# Where to Find Asio Release Notes: Official Sources and Version History

> Discover where to find Asio release notes. Explore official GitHub Releases, Git tags, and internal documentation for the latest updates and version history.

- Repository: [chriskohlhoff/asio](https://github.com/chriskohlhoff/asio)
- Tags: api-reference
- Published: 2026-07-16

---

**You can find Asio release notes on the GitHub Releases page, in Git tag descriptions, or in the repository's internal documentation files like `doc/release_checklist.htm` and `README`.**

When tracking changes to the Asio networking library, knowing where to locate official Asio release notes helps you understand what changed, when it released, and whether you need to upgrade. The **chriskohlhoff/asio** repository maintains version history across multiple locations, from user-facing GitHub Releases to internal source files that the [`release.pl`](https://github.com/chriskohlhoff/asio/blob/main/release.pl) script updates automatically.

## GitHub Releases: The Primary Source for Asio Release Notes

The most accessible location for Asio release notes is the **GitHub Releases** page at `https://github.com/chriskohlhoff/asio/releases`. This page provides a chronological list of versioned releases, each containing a short changelog, download links for source archives, and links to the associated Git tag.

Each release entry corresponds to a specific version tag (e.g., `asio-1.28.0`) and includes the same notes that appear in the tag description.

## Git Tags: The Canonical Source of Truth

For programmatic access or verification of exact release commits, the **Git tags** at `https://github.com/chriskohlhoff/asio/tags` serve as the canonical source. Each tag (e.g., `asio-1.28.0`) marks the exact commit that constitutes a release.

The tag description contains the release notes, making this location ideal for scripting or automation that needs to parse version history directly from the repository metadata.

## Repository Files That Track Release Information

### `doc/release_checklist.htm`: The Internal Release Checklist

Located at `doc/release_checklist.htm` in the repository root, this file serves as the internal checklist used when a new version is cut. It lists the items that must be verified for a release and includes a short "released on ..." line that confirms the release date.

This file provides insight into the release process and verification steps.

### `README`: Auto-Updated Version Header

The `README` file at the repository root displays the current version in the header, showing "asio version X.Y.Z" and "Released <date>." This file is automatically patched by the [`release.pl`](https://github.com/chriskohlhoff/asio/blob/main/release.pl) script when a new release is made, making it a reliable quick-reference for the latest version information without navigating to GitHub Releases.

### [`include/asio/version.hpp`](https://github.com/chriskohlhoff/asio/blob/main/include/asio/version.hpp): The Version Macro Definition

For developers integrating Asio into their projects, [`include/asio/version.hpp`](https://github.com/chriskohlhoff/asio/blob/main/include/asio/version.hpp) defines the numeric `ASIO_VERSION` macro and the human-readable version string. This header is updated on each release and allows compile-time version checking in your code.

## How Release Automation Updates These Files

The [`release.pl`](https://github.com/chriskohlhoff/asio/blob/main/release.pl) script in the repository automates the release process. When executed, it updates the `README` with the new version and release date, patches [`include/asio/version.hpp`](https://github.com/chriskohlhoff/asio/blob/main/include/asio/version.hpp) with the updated `ASIO_VERSION` macro, and ensures consistency across the documentation.

```cpp
// Example: printing the Asio version at runtime
#include <asio.hpp>
#include <iostream>

int main()
{
    std::cout << "Asio version: " << ASIO_VERSION << "\n";
    std::cout << "Header reports: " << ASIO_VERSION << "\n";
}

```

The `ASIO_VERSION` macro reflects the value that [`release.pl`](https://github.com/chriskohlhoff/asio/blob/main/release.pl) writes into [`include/asio/version.hpp`](https://github.com/chriskohlhoff/asio/blob/main/include/asio/version.hpp) when a new release is cut.

## Summary

- The **GitHub Releases** page (`github.com/chriskohlhoff/asio/releases`) provides the most user-friendly access to Asio release notes with changelogs and download links.
- **Git tags** contain the canonical release notes and mark the exact commits for each version, useful for programmatic access.
- Internal files like `doc/release_checklist.htm`, `README`, and [`include/asio/version.hpp`](https://github.com/chriskohlhoff/asio/blob/main/include/asio/version.hpp) track version metadata and release dates, updated automatically by the [`release.pl`](https://github.com/chriskohlhoff/asio/blob/main/release.pl) script.
- The `ASIO_VERSION` macro in [`include/asio/version.hpp`](https://github.com/chriskohlhoff/asio/blob/main/include/asio/version.hpp) enables compile-time version checking in C++ applications.

## Frequently Asked Questions

### Where are the official Asio release notes published?

The official Asio release notes are published on the GitHub Releases page for the chriskohlhoff/asio repository. Each release includes a changelog, download links, and links to the specific Git tag. You can also find the same notes in the Git tag descriptions.

### How can I check which Asio version I have installed?

Check the `ASIO_VERSION` macro defined in [`include/asio/version.hpp`](https://github.com/chriskohlhoff/asio/blob/main/include/asio/version.hpp). This header is updated with every release and provides both numeric and human-readable version strings. You can also print this value at runtime using `std::cout << ASIO_VERSION;`.

### What is the [`release.pl`](https://github.com/chriskohlhoff/asio/blob/main/release.pl) script in the Asio repository?

The [`release.pl`](https://github.com/chriskohlhoff/asio/blob/main/release.pl) script is an automation tool that updates version information across the repository during a release. It patches the `README` with the new version and date, updates [`include/asio/version.hpp`](https://github.com/chriskohlhoff/asio/blob/main/include/asio/version.hpp) with the correct `ASIO_VERSION` macro, and ensures documentation consistency.

### Is there a release checklist for Asio versions?

Yes. The file `doc/release_checklist.htm` contains the internal checklist used when preparing a new release. It lists verification steps and includes a release date confirmation, providing transparency into the release process.