> ## Documentation Index > Fetch the complete documentation index at: https://docs.adcontextprotocol.org/llms.txt > Use this file to discover all available pages before exploring further. # Versions & Compatibility > Every published AdCP version, its status, and its end-of-life date. Start here if you're choosing or upgrading a version. ## At a glance **Choosing today:** new production integrations should use 3.1 with wire pin `"3.1"`. Existing 3.0 integrations can remain pinned to `"3.0"` while they migrate. | Status | Versions | Wire pin | What it means | | ----------------- | ---------------------------- | -------- | ------------------------------------------------------------------------------------------------------------------------------------ | | **Active** | 3.1 (current stable: 3.1.0) | `"3.1"` | Current production minor release. See [What's New in AdCP 3.1](/docs/reference/whats-new-in-3-1) for the feature set. | | **Maintained** | 3.0 (current stable: 3.0.19) | `"3.0"` | Supported previous minor for existing production integrations. Receives compatibility and security patches. | | **Security-only** | 2.5.0, 2.5.1, 2.5.3 | `"2.5"` | Security patches through **August 1, 2026 (UTC)**. Not safe for AAO-network production — see [v2 sunset](/docs/reference/v2-sunset). | | **End of life** | 2.0.0, 2.1.0 | — | No patches. Migrate to 3.0. | | **Planned** | 3.2, 4.0 | — | Targets in [planned releases](/docs/reference/versioning#planned-releases). | **Wire values are release-precision only.** Send `"3.1"` for the stable 3.1 line or `"3.0"` for the maintained 3.0 line. Do not send patch components like `"3.0.19"` or full semver pre-release values like `"3.1.0-rc.15"`. Historical prerelease pins such as `"3.1-rc.15"` remain valid only for agents that explicitly advertise those prerelease values. See [patches are not negotiated](/docs/reference/versioning#patches-are-not-negotiated). *Status legend: Active = current stable generation. Maintained = supported previous minor. Security-only = patches for security issues only, no features. End of life = no patches. Planned = not yet released.* ## All published versions ### 3.x — current generation | Version | Released | Notes | | ------------------------- | ------------------------ | --------------------------------------------------------------------------- | | 3.0.0 | 2026-04-22 | GA — stable baseline for the 3.x cycle. | | 3.0.1 through 3.0.10 | 2026-04-28 to 2026-05-10 | Patches. Wire-compatible with 3.0.0. | | 3.0.11 through 3.0.15 | 2026-05-11 to 2026-05-31 | Patches. Wire-compatible with 3.0.0. | | 3.0.16 through **3.0.19** | 2026-06-14 to 2026-06-17 | Patches. **3.0.19 is the latest stable patch.** Wire-compatible with 3.0.0. | | **3.1.0** | 2026-06-18 | GA — current production minor release. Use wire pin `"3.1"`. | Patches don't change the wire contract. Upgrading within 3.0.x is always safe, and 3.1 remains additive over 3.0. For per-version detail, see [Release Notes](/docs/reference/release-notes) (curated narrative) and the [Changelog](/docs/reference/changelog) (full technical history). ### Prereleases (superseded) | Version | Released | Notes | | ------------------------------ | ------------------------ | -------------------------------------------------------------------------------------------------------------------- | | 3.1.0-rc.1 through 3.1.0-rc.15 | 2026-05-29 to 2026-06-16 | Superseded by 3.1.0 GA. These artifacts remain available for pinned prerelease adopters and release forensics. | | 3.0.0-beta.1 through rc.2 | 2026-01-26 to 2026-03-15 | Superseded. | | 3.0.0-rc.3 | 2026-04-01 | Superseded by GA. See [prerelease upgrade notes](/docs/reference/migration/prerelease-upgrades) if you adopted rc.3. | ### 2.x — sunsetting | Version | Released | Notes | | ------- | ------------ | -------------------------------------------------------------- | | 2.0.0 | 2025-10-15 | End of life. No patches. Migrate to 3.0. | | 2.1.0 | 2025-10-19 | End of life. No patches. Migrate to 3.0. | | 2.5.0 | 2025-11-22 | Security-only through Aug 1, 2026 (UTC). | | 2.5.1 | 2025-12-24 | Security-only through Aug 1, 2026 (UTC). | | 2.5.3 | January 2026 | Security-only through Aug 1, 2026 (UTC). **Last 2.x release.** | After August 1, 2026 (UTC), the entire 2.x line is fully deprecated. The 2.x schema URLs continue to resolve so existing integrations don't break silently, but those schemas receive no further updates. See [v2 Sunset](/docs/reference/v2-sunset) for migration paths. ## FAQ ### What's "current"? For new production integrations, **3.1.0** is current; pin your integration to `"3.1"` (not `"3.1.0"`). Existing 3.0 integrations can remain pinned to `"3.0"` while they migrate. See [Version negotiation](/docs/reference/versioning#version-negotiation). ### What happened to 2.2, 2.3, 2.4, 2.6? The 2.x line skipped version numbers during its working-group cycle. Some appear as in-flight changelog entries but were never released — the changes were rolled forward into the next published version or deferred to 3.0. The five published 2.x releases are 2.0.0, 2.1.0, 2.5.0, 2.5.1, and 2.5.3. ### Can I still register a v2 agent? Yes — v2 agents can be registered in the AAO registry but cannot be AAO Verified. Certification and verified-default discovery require v3.x. See [v2 Sunset → If you use the AAO registry](/docs/reference/v2-sunset#if-you-use-the-aao-registry). ### How long will 3.0 be supported? At least 12 months after 4.0 GA. See [Versioning → Support window for previous major](/docs/reference/versioning#support-window-for-previous-major). ### Where is 4.0? Targeted for early 2027. 3.x is mid-cycle — see the [planned releases table](/docs/reference/versioning#planned-releases). ## Choosing a version | If you are… | Use | | ------------------------------------------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | Building a new production integration today | **3.1**. Pin `"3.1"` on the wire. | | Running an existing 3.0 integration | Stay on **3.0** while you migrate, or move to **3.1** when your SDK and validation are ready. | | Running a 2.5.x integration | Migrate to 3.0 before **Aug 1, 2026 (UTC)**. Start with the [migration guide](/docs/reference/migration). | | Running a 2.0 or 2.1 integration | Upgrade now — out of support. | | Trying a post-3.1 unreleased feature | See [Release Notes](/docs/reference/release-notes), [Versioning & Governance](/docs/reference/versioning), and [experimental status](/docs/reference/experimental-status). | ## Related * **[Versioning & Governance](/docs/reference/versioning)** — release tiers, schema-change scope, cadence policy * **[v2 Sunset](/docs/reference/v2-sunset)** — full v2 end-of-life timeline and migration paths * **[What's new in v3](/docs/reference/whats-new-in-v3)** — feature-by-feature summary of what 3.0 adds * **[What's New in AdCP 3.1](/docs/reference/whats-new-in-3-1)** — final 3.1 feature set and adopter actions * **[Release Notes](/docs/reference/release-notes)** — curated narrative for each version * **[Changelog](/docs/reference/changelog)** — full technical change history