diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 04b3745..d129ce0 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -49,7 +49,7 @@ jobs:
     strategy:
       fail-fast: false # If one platform fails, allow the rest to keep testing.
       matrix:
-        python-version: ["3.8", "3.9", "3.10", "3.11", "3.12", "3.13", "3.14", "3.14t"]
+        python-version: ["3.8", "3.9", "3.10", "3.11", "3.12", "3.13", "3.14", "3.14t", "3.15-dev", "3.15t-dev"]
         os: ["macos-latest", "ubuntu-latest", "windows-latest"]
         rust: [stable]
         include:
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 873c2c2..b3202ad 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,7 @@
-## Unreleased
+## 0.29.0 - 2026-05-12
+
 - Update `pyo3` to 0.29.
+- Support serializing `i128` and `u128`.
 
 ## 0.28.0 - 2026-02-18