From 6a3dfb64a1da4f4d95aae2702d16a4cdf71dd19a Mon Sep 17 00:00:00 2001
From: igerber <isaac.gerber@gmail.com>
Date: Tue, 27 Jan 2026 07:23:10 -0500
Subject: [PATCH] Bump version to 2.2.0

Release highlights:
- Windows wheel builds using pure-Rust faer library
- Rust backend migrated from nalgebra/ndarray to faer
- Improved numerical stability and fallback handling

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
---
 CHANGELOG.md          | 24 ++++++++++++++++++++++++
 diff_diff/__init__.py |  2 +-
 pyproject.toml        |  2 +-
 rust/Cargo.toml       |  2 +-
 4 files changed, 27 insertions(+), 3 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index f09244e..5f215d2 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -5,6 +5,29 @@ 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).
 
+## [2.2.0] - 2026-01-27
+
+### Added
+- **Windows wheel builds** using pure-Rust `faer` library for linear algebra (PR #115)
+  - Eliminates external BLAS/LAPACK dependencies (no OpenBLAS or Intel MKL required)
+  - Enables cross-platform wheel builds for Linux, macOS, and Windows
+  - Simplifies installation on all platforms
+
+### Changed
+- **Rust backend migrated from nalgebra/ndarray to faer** (PR #115)
+  - OLS solver now uses faer's SVD implementation
+  - Robust variance estimation uses faer's matrix operations
+  - TROP distance calculations use faer primitives
+  - Maintains numerical parity with existing NumPy backend
+
+### Fixed
+- **Rust backend numerical stability improvements** (PR #115)
+  - Improved singular matrix detection with condition number checks
+  - NaN propagation in variance-covariance estimation
+  - Fallback to Python backend on numerical instability with warning
+  - Underdetermined SVD handling (n < k case)
+- **macOS CI compatibility** for Python 3.14 with `PYO3_USE_ABI3_FORWARD_COMPATIBILITY`
+
 ## [2.1.9] - 2026-01-26
 
 ### Added
@@ -584,6 +607,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
   - `to_dict()` and `to_dataframe()` export methods
   - `is_significant` and `significance_stars` properties
 
+[2.2.0]: https://github.com/igerber/diff-diff/compare/v2.1.9...v2.2.0
 [2.1.9]: https://github.com/igerber/diff-diff/compare/v2.1.8...v2.1.9
 [2.1.8]: https://github.com/igerber/diff-diff/compare/v2.1.7...v2.1.8
 [2.1.7]: https://github.com/igerber/diff-diff/compare/v2.1.6...v2.1.7
diff --git a/diff_diff/__init__.py b/diff_diff/__init__.py
index acab282..9b83a83 100644
--- a/diff_diff/__init__.py
+++ b/diff_diff/__init__.py
@@ -136,7 +136,7 @@
     load_mpdta,
 )
 
-__version__ = "2.1.9"
+__version__ = "2.2.0"
 __all__ = [
     # Estimators
     "DifferenceInDifferences",
diff --git a/pyproject.toml b/pyproject.toml
index 288185e..a401497 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -4,7 +4,7 @@ build-backend = "maturin"
 
 [project]
 name = "diff-diff"
-version = "2.1.9"
+version = "2.2.0"
 description = "A library for Difference-in-Differences causal inference analysis"
 readme = "README.md"
 license = "MIT"
diff --git a/rust/Cargo.toml b/rust/Cargo.toml
index 5fe9f87..d3530da 100644
--- a/rust/Cargo.toml
+++ b/rust/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "diff_diff_rust"
-version = "2.1.9"
+version = "2.2.0"
 edition = "2021"
 description = "Rust backend for diff-diff DiD library"
 license = "MIT"