diff --git a/CHANGELOG.md b/CHANGELOG.md
index ed40bdc..e8ca0ff 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,8 +1,45 @@
 # Changelog
 
-All notable changes to this project are documented here. The format follows [Keep a Changelog](https://keepachangelog.com/en/1.1.0/), and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html) once it reaches 1.0.0. Pre-1.0 releases MAY change the ACS-Core baseline in patch versions; the wire format version (`acs_version` in the handshake) evolves separately in the `specification/` directory.
+All notable changes to this project are documented here. The format follows [Keep a Changelog](https://keepachangelog.com/en/1.1.0/), and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html) once it reaches 1.0.0. Pre-1.0 releases MAY change the ACS-Core baseline and the Trace mappings in patch versions. The wire format version (`acs_version` in the handshake, and the `v0.1.0` in every schema `$id`) evolves separately in the `specification/` directory.
 
-## [0.1.3] — 2026-09-09
+## [0.1.4] - 2026-10-16
+
+This release changes ACS-Trace for producers and consumers. The specification version stays v0.1.0, so the files at the `/schema/v0.1.0/` URIs change in place, and the handshake cannot tell the old rules from the new. Name this release, or its commit, when you claim ACS-Trace conformance.
+
+### Changed: Trace (breaking)
+
+- Every step span now requires `acs.request_id` and `acs.session.id`. A reader joins the two parties' spans on that pair. An exporter that omits either no longer conforms ([PR #275](https://github.com/GenAI-Security-Project/agent-control-standard/pull/275), issue #228).
+- The OCSF decision class now requires `finding_info`, `finding_info.title`, `action_id`, `action`, `disposition_id`, `disposition`, `evidences` and `metadata.correlation_uid`, and decision events list the `security_control` profile. `defer` maps to `disposition_id` 99. `is_alert` is true exactly when `severity_id` is 3 or higher, so deny, ask and defer alert, and allow and modify don't. A decision that arrives late is emitted and flagged in `finding_info.types`, where it used to be suppressed (PR #275).
+- A decision event records the Guardian's verdict, not the enforced outcome. A matching `acs.decision.failure` in either party's stream means the decision MUST NOT be counted as enforced (PR #275).
+- The four `policy_references` fields and the provenance `source_id` now require `minLength: 1` (PR #275, issue #263).
+- The OCSF mapping is pinned to OCSF 1.9.0 and uses its class names. Three rows on class 5001 set `activity_id` 2, and `required_fields` includes `finding_info` ([PR #258](https://github.com/GenAI-Security-Project/agent-control-standard/pull/258)).
+
+### Added
+
+- The `acs.decision.failure` span event, and the extra `acs.decision` attributes a reader needs to replay a decision from the trace alone (PR #275).
+- Per-hook `conditional_attributes` in `otel-mapping.json` ([PR #261](https://github.com/GenAI-Security-Project/agent-control-standard/pull/261)).
+- Trace mappings for the skill lifecycle hooks, `steps/skillRegister`, `steps/skillLoad` and `steps/skillUnload`, in both OpenTelemetry and OCSF ([PR #63](https://github.com/GenAI-Security-Project/agent-control-standard/pull/63), issue #57, issue #58).
+- The reference Guardian exports OTLP traces to a file and over HTTP, and a converter turns the host adapter's audit log into the same format. It covers the two hook methods the Guardian evaluates and is not an ACS-Trace conformance claim ([PR #244](https://github.com/GenAI-Security-Project/agent-control-standard/pull/244), issue #91).
+- A committed sample trace, a test that holds the exporter to the mapping, and "Produce a trace", a walkthrough from a fresh clone to a trace file, tested natively and with Docker ([PR #277](https://github.com/GenAI-Security-Project/agent-control-standard/pull/277), issue #266).
+- "How the reference Guardian produces a trace" on the Trace with OpenTelemetry page, with diagrams of both streams and of one tool call, and a Troubleshooting list in the Guardian README ([PR #280](https://github.com/GenAI-Security-Project/agent-control-standard/pull/280)).
+
+### Changed: reference implementation
+
+- The audit converter's spans carry `service.name` `acs-reference-audit-converter`, no longer the Guardian's `acs-reference-guardian`. A query that filtered on the old value for converter spans needs updating (PR #277, issue #274).
+- The converter refuses to write to an output file that already exists and exits 1. It used to append, which could write OTLP lines into the audit log or double every span on a rerun (PR #277).
+- `otel-collector.yaml` stays on loopback, keeps its file across restarts, writes owner-only, and pins its container image by digest (PR #277, issue #276).
+- `OTEL_TRACES_*`, `OTEL_SPAN_*`, `OTEL_ATTRIBUTE_*`, `OTEL_BSP_*` and OTLP compression variables no longer change what the Guardian or the converter exports. `OTEL_EXPORTER_OTLP_*HEADERS` still apply (PR #277).
+- A loopback trace endpoint is added to whichever of `NO_PROXY` and `no_proxy` is set, keeping the user's own entries, and the Guardian warns at startup when a proxy is set and loopback isn't exempt. The walkthrough says to stop the Guardian and the collector before deleting `.acs` ([PR #279](https://github.com/GenAI-Security-Project/agent-control-standard/pull/279), issue #274).
+
+### Removed
+
+- `acs.provenance.lineage_depth` and `acs.provenance.origins_compacted` from the OTel mapping (PR #261).
+
+### Changed: dependencies
+
+- urllib3 2.7.0 to 2.8.0 ([PR #202](https://github.com/GenAI-Security-Project/agent-control-standard/pull/202)).
+
+## [0.1.3] — 2026-10-05
 
 ### Changed — ACS-Core baseline
 
diff --git a/pyproject.toml b/pyproject.toml
index bed93b4..52430de 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -1,6 +1,6 @@
 [project]
 name = "acs"
-version = "0.1.3"
+version = "0.1.4"
 description = "ACS Documentation"
 license = "Apache-2.0"
 requires-python = ">=3.11"
diff --git a/uv.lock b/uv.lock
index d52e51d..dd6b15d 100644
--- a/uv.lock
+++ b/uv.lock
@@ -4,7 +4,7 @@ requires-python = ">=3.11"
 
 [[package]]
 name = "acs"
-version = "0.1.3"
+version = "0.1.4"
 source = { virtual = "." }
 dependencies = [
     { name = "mike" },
diff --git a/version.txt b/version.txt
index b1e80bb..845639e 100644
--- a/version.txt
+++ b/version.txt
@@ -1 +1 @@
-0.1.3
+0.1.4