diff --git a/ceres-solver-sys/CHANGELOG.md b/ceres-solver-sys/CHANGELOG.md
index 5f10346..52c1ade 100644
--- a/ceres-solver-sys/CHANGELOG.md
+++ b/ceres-solver-sys/CHANGELOG.md
@@ -31,6 +31,16 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 --
 
+## [0.5.1] 2025-12-13
+
+### Fixed
+
+- Building issues caused by Rust edtion bump to 2024, changed back to 2021.
+
+### Changed
+
+- Revert Rust edition from 2024 back to 2021, set resolver explicitly to 3 to support MSRV-aware dependency resolution.
+
 ## [0.5.0] 2025-12-13
 
 ### Changed
diff --git a/ceres-solver-sys/Cargo.toml b/ceres-solver-sys/Cargo.toml
index 0952e1e..79c5846 100644
--- a/ceres-solver-sys/Cargo.toml
+++ b/ceres-solver-sys/Cargo.toml
@@ -1,7 +1,8 @@
 [package]
 name = "ceres-solver-sys"
-version = "0.5.0"
-edition = "2024"
+version = "0.5.1"
+edition = "2021"
+resolver = "3"
 readme = "README.md"
 description = "Unsafe Rust bindings for the Ceres Solver"
 repository = "https://github.com/light-curve/ceres-solver-rs"