diff --git a/CHANGELOG.md b/CHANGELOG.md
index aeeb545..6309217 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -5,6 +5,24 @@ All notable changes to this project will be documented in this file.
 The format is based on [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).
 
+## [0.4.1] - 2026-10-12
+
+### Fixed
+
+- **Receipts from Pipelock parallel receipt chains now verify.** `verify()` and
+  `verify_chain()` accept the optional `group_binding` object that Pipelock signs
+  into `session_open` when `flight_recorder.receipt_chains` is greater than 1.
+  Before this release every shard of a grouped run failed with an unknown signed
+  field error. The binding is part of the signed projection in Go field order.
+  This is per-receipt and per-chain compatibility only: whole-group verification
+  (signed open and close manifests, shard membership, missing shards, the link to
+  a previous group and recovery tails) still needs Pipelock's own group verifier.
+  Receipts from single-chain runs verify as before.
+
+### Documentation
+
+- **The README states what a valid result does not prove.** It no longer says exit codes match `pipelock verify-receipt` or that the package mirrors the Go verifier without qualification. A valid chain is not proof that its end is present, a valid shard is not proof that a parallel-chain group is complete, and entries other than ActionReceipt v1 in a recorder file are not checked.
+
 ## [0.4.0] - 2026-07-30
 
 ### Added
diff --git a/README.md b/README.md
index d182737..4cd03c8 100644
--- a/README.md
+++ b/README.md
@@ -9,7 +9,7 @@
 
 **Python verifier for [Pipelock](https://github.com/luckyPipewrench/pipelock) receipts.** Supports **ActionReceipt v1** chains and individual **EvidenceReceipt v2** envelopes for contract-aware lifecycle events. Verifies Ed25519 signatures, v1 chain linkage, v2 payload schemas, key-purpose authority, and flight-recorder wrapping.
 
-Mirrors the Go reference implementation byte-for-byte. The conformance golden files in `tests/conformance/` are generated by Pipelock's Go code and verified identically by both sides.
+Mirrors the Go reference implementation's signature, chain-linking and canonical-form checks byte-for-byte. The conformance golden files in `tests/conformance/` are generated by Pipelock's Go code and verified identically by both sides. It does not implement the end-of-chain proof or the whole-group verification that newer Pipelock releases add; see the section "What a valid result does and does not prove" below.
 
 [Install](#install) · [Usage](#usage) · [EvidenceReceipt v2](#evidencereceipt-v2) · [Well-known directory](#well-known-directory) · [What gets verified](#what-gets-verified) · [Spec](https://pipelab.org/learn/action-receipt-spec/) · [Go reference](https://github.com/luckyPipewrench/pipelock)
 
@@ -116,7 +116,13 @@ python -m pipelock_verify evidence.jsonl \
   --rotation-endorsement receipt-rotation-2026-07-30.json
 ```
 
-Exit codes match `pipelock verify-receipt`: 0 on success, 1 on failure.
+Exit codes: 0 on success, 1 on failure. In Pipelock releases that add end-of-chain proofs, `pipelock verify-receipt` also exits 3 for a valid chain whose end is not proven. This package has no such state.
+
+### What a valid result does and does not prove
+
+`CHAIN VALID` means every ActionReceipt v1 extracted from the file has a valid signature, the signer matches, and each receipt links to the one before it. Other entries in a flight-recorder file are not checked here: altering the signature on a wrapped EvidenceReceipt v2 entry still returns `CHAIN VALID`, while Pipelock's own `pipelock verify-receipt` rejects the recorder. It also does not prove the chain ends where it should. A chain cut off after a receipt still verifies, because this package has no end-of-chain proof. The exception is a chain verified with a rotation endorsement: cutting it before the rotation boundary leaves the endorsement unused, and that is rejected. In Pipelock releases that add end-of-chain proofs, `pipelock verify-receipt` reports a chain with no proven end as `VALID PREFIX, END UNPROVEN`. Use it when a missing tail matters.
+
+Parallel receipt chains (`flight_recorder.receipt_chains` greater than 1) write one chain per shard. Each shard verifies on its own with this package, but a valid shard does not show that the group is complete. Shard membership, missing shards, the signed group open and close, and the link to a previous group still need Pipelock's own group verifier.
 
 ## EvidenceReceipt v2
 
diff --git a/pipelock_verify/__init__.py b/pipelock_verify/__init__.py
index 24a5475..05fb007 100644
--- a/pipelock_verify/__init__.py
+++ b/pipelock_verify/__init__.py
@@ -65,7 +65,7 @@
     verify_chain,
 )
 
-__version__ = "0.4.0"
+__version__ = "0.4.1"
 
 __all__ = [
     "PAYLOAD_AUTHORITY",
diff --git a/pipelock_verify/__main__.py b/pipelock_verify/__main__.py
index e5752b7..75f5853 100644
--- a/pipelock_verify/__main__.py
+++ b/pipelock_verify/__main__.py
@@ -1,8 +1,9 @@
 """Command-line interface for ``python -m pipelock_verify``.
 
 Verifies a single receipt JSON file or a flight recorder JSONL chain.
-Exit code 0 on success, 1 on failure — same convention as the Go
-``pipelock verify-receipt`` command.
+Exit code 0 on success, 1 on failure. Pipelock releases that add end-of-chain
+proofs also exit 3 from ``pipelock verify-receipt`` for a valid chain whose end
+is not proven; this CLI has no such state.
 """
 
 from __future__ import annotations
diff --git a/pyproject.toml b/pyproject.toml
index 1553924..2c50099 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -4,7 +4,7 @@ build-backend = "setuptools.build_meta"
 
 [project]
 name = "pipelock-verify"
-version = "0.4.0"
+version = "0.4.1"
 description = "Verify Pipelock receipts: ActionReceipt v1 chains and individual EvidenceReceipt v2 envelopes."
 readme = "README.md"
 license = "Apache-2.0"