diff --git a/CHANGELOG.md b/CHANGELOG.md
index 9089720..93af019 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -7,6 +7,12 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+## [0.13.0] - 2026-06-01
+
+### Added
+
+- OTLP protobuf export: the `ProtobufEncoder` in `@moontrace/otlp/transport` now encodes `ExportTraceServiceRequest` / `ExportLogsServiceRequest` to protobuf wire bytes (`application/x-protobuf`), hand-rolled against the `moonbitlang/protobuf` runtime — no codegen or external OTLP bindings. Trace/span IDs are written as bytes, timestamps as fixed64, span flags as fixed32; the wire format is checked by round-trip decode and a golden fixture generated from `google.protobuf`. Select the encoding via `OtlpEncoder`; the JSON path is unchanged (#63).
+
 ## [0.12.0] - 2026-06-01
 
 Adds the native buffered file subscriber package.
diff --git a/moon.mod b/moon.mod
index b78f0ef..c41d02a 100644
--- a/moon.mod
+++ b/moon.mod
@@ -1,6 +1,6 @@
 name = "brickfrog/moontrace"
 
-version = "0.12.0"
+version = "0.13.0"
 
 import {
   "moonbitlang/async@0.19.0",