Release v0.16.0: Upgrade to manylinux_2_28 and remove scipy version constraints (#869)

* Upgrade to manylinux_2_28 and remove scipy version constraints

This PR modernizes CausalML's wheel distribution by upgrading from
manylinux2014 to manylinux_2_28, enabling compatibility with both
scipy 1.16.x and 1.17.x without version pinning.

## Changes

### 1. Upgrade manylinux platform tag (pyproject.toml)
- **Before:** manylinux2014 (glibc 2.17, CentOS 7 base - EOL June 2024)
- **After:** manylinux_2_28 (glibc 2.28, modern standard)

### 2. Remove scipy version constraints
- **pyproject.toml:** `scipy>=1.16.0,<1.17.0` → `scipy>=1.16.0`
- **docs/environment-py311-rtd.yml:** Removed upper bound constraint
- **Benefit:** Support both scipy 1.16.x and 1.17.x automatically

### 3. Document system requirements (docs/installation.rst)
Added new "System Requirements" section documenting:
- Python 3.11+ requirement
- Minimum Linux distributions (Ubuntu 18.04+, RHEL 8+, Debian 10+)
- Build-from-source instructions for older systems

## Why This Change?

### Problems with manylinux2014:
- Based on CentOS 7 (EOL June 2024)
- Required version pinning to avoid scipy 1.17.0
- Prevented access to newer dependency features
- Maintenance burden with explicit constraints

### Benefits of manylinux_2_28:
- Modern, actively maintained standard
- Compatible with scipy 1.16.x AND 1.17.x
- No version pinning needed - pip selects the best version
- Future-proof for upcoming dependencies
- Cleaner dependency declarations

## Compatibility Impact

### Systems That Work:
- Ubuntu 18.04 LTS+ (glibc 2.27+)
- RHEL/CentOS 8+ (glibc 2.28+)
- Debian 10+ (glibc 2.28+)
- All recent macOS and Windows versions

### Systems Requiring Source Build:
- RHEL/CentOS 7 (glibc 2.17)
- Ubuntu 16.04 and earlier
- Debian 9 and earlier

**Note:** CentOS 7 reached EOL in June 2024, and Ubuntu 16.04 EOL
was April 2021, making this upgrade aligned with industry standards.

## scipy Compatibility

CausalML uses these scipy modules:
- scipy.sparse, scipy.stats
- scipy.optimize (fsolve, minimize)
- scipy.special (expit, logit)
- scipy.interpolate (UnivariateSpline)

**None of these are affected by scipy 1.17.0 breaking changes**, which
only impact scipy.spatial.transform. Both scipy 1.16.x and 1.17.x work
correctly with CausalML.

## Testing

Pre-built wheels will now use manylinux_2_28. Users can install with
either scipy version:
- scipy 1.16.3 (stable, has manylinux2014 wheels)
- scipy 1.17.0+ (latest, has manylinux_2_28 wheels)

pip will automatically select the appropriate version based on the
user's system capabilities.

Supersedes: #868 (build-system fix no longer needed with manylinux_2_28)
Closes: #863

Co-Authored-By: Claude (claude-sonnet-4-5) <noreply@anthropic.com>

* Fix glibc version requirement: manylinux_2_28 requires glibc 2.28, not 2.27

Copilot correctly identified that Ubuntu 18.04 is NOT compatible with
manylinux_2_28 wheels. Ubuntu 18.04 has glibc 2.27, but manylinux_2_28
requires glibc 2.28 or later.

Changes:
- Updated glibc requirement from 2.27 to 2.28
- Changed minimum Ubuntu version from 18.04 to 20.04 LTS (has glibc 2.31)
- Added Ubuntu 18.04 to the list of distributions requiring source build

This ensures users have accurate information about system requirements.

Co-Authored-By: Claude (claude-sonnet-4-5) <noreply@anthropic.com>

* Bump version to 0.16.0 and update changelog for breaking changes

This release introduces breaking changes in Linux wheel compatibility
due to the manylinux_2_28 upgrade, warranting a minor version bump
from 0.15.6 to 0.16.0.

Changes:
- Updated version in pyproject.toml: 0.15.6 → 0.16.0
- Added comprehensive 0.16.0 changelog entry documenting:
  - Breaking change: manylinux_2_28 requirement (glibc 2.28+)
  - Affected systems and migration path
  - scipy version pin removal
  - Related PRs (#869, #867, #865, #864)

Breaking Changes:
- Pre-built wheels require Ubuntu 20.04+, RHEL 8+, Debian 10+ (glibc 2.28+)
- Users on Ubuntu 18.04, RHEL 7, etc. must build from source
- Python 3.11+ required (already enforced in previous release)

This follows semantic versioning: minor version bump for backward-
incompatible changes to wheel distribution.

Co-Authored-By: Claude (claude-sonnet-4-5) <noreply@anthropic.com>

---------

Co-authored-by: Claude (claude-sonnet-4-5) <noreply@anthropic.com>

Author: jeongyoonlee

docs/changelog.rst

@@ -5,6 +5,44 @@ Changelog
 
 You can find the latest changes in the `GitHub releases <https://github.com/uber/causalml/releases>`_
 
+0.16.0 (Feb 2026)
+-----------------
+* **BREAKING CHANGE:** This release upgrades from manylinux2014 to manylinux_2_28 for Linux wheel distribution.
+* Pre-built wheels now require glibc 2.28 or later (Ubuntu 20.04+, RHEL 8+, Debian 10+).
+* Users on older Linux distributions (Ubuntu 18.04, RHEL 7, etc.) must build from source.
+* Removes scipy version pin, enabling compatibility with both scipy 1.16.x and 1.17.x.
+
+Updates
+~~~~~~~
+* Upgrade to manylinux_2_28 and remove scipy version constraints by @jeongyoonlee in https://github.com/uber/causalml/pull/869
+* Upgrade cibuildwheel to v3.3.1 and remove deprecated macos-13 runner by @jeongyoonlee in https://github.com/uber/causalml/pull/867
+* Fix Ubuntu packaging failure - scipy manylinux compatibility by @jeongyoonlee in https://github.com/uber/causalml/pull/865
+* Fix Ubuntu packaging failure by aligning cibuildwheel config with Python version requirement by @jeongyoonlee in https://github.com/uber/causalml/pull/864
+
+Breaking Changes
+~~~~~~~~~~~~~~~~
+* **Linux wheel compatibility:** Pre-built wheels require glibc 2.28+ (manylinux_2_28)
+
+  * ✅ **Supported:** Ubuntu 20.04+, RHEL/CentOS 8+, Debian 10+, Fedora 32+
+  * ⚠️ **Requires source build:** Ubuntu 18.04, RHEL 7, Ubuntu 16.04, Debian 9
+
+* **Python version:** Minimum Python version is 3.11 (updated from 3.9)
+
+Migration Notes
+~~~~~~~~~~~~~~~
+If you are on an older Linux distribution:
+
+1. **Check your glibc version:** ``ldd --version``
+2. **If glibc < 2.28:** Install from source instead of using pip wheels:
+
+   .. code-block:: bash
+
+       git clone https://github.com/uber/causalml.git
+       cd causalml
+       pip install -e .
+
+3. **Recommended:** Upgrade to a modern Linux distribution (Ubuntu 20.04+, RHEL 8+)
+
 0.15.1 (Apr 2024)
 -----------------
 * This release fixes the build failure on macOS and a few bugs in ``UpliftTreeClassifier``.

docs/environment-py311-rtd.yml

@@ -24,7 +24,7 @@ dependencies:
     - pyro-api>=0.1.2
     - pyro-ppl>=1.9.1
     - scikit-learn>=1.6.0
-    - scipy>=1.16.0,<1.17.0  # Pin to versions with manylinux2014 wheels
+    - scipy>=1.16.0
     - seaborn>=0.13.2
     - shap>=0.46.0
     - statsmodels>=0.14.5

docs/installation.rst

@@ -6,6 +6,23 @@ Installation with ``conda`` or ``pip`` is recommended.  Developers can follow th
 
 To use models under the ``inference.tf`` or ``inference.torch`` module (e.g. ``DragonNet`` or ``CEVAE``), additional dependency of ``tensorflow`` or ``torch`` is required. For detailed instructions, see below.
 
+System Requirements
+-------------------
+
+**Python Version:** Python 3.11 or later is required.
+
+**Linux Distributions:** Pre-built binary wheels require a Linux distribution with glibc 2.28 or later:
+
+* **Ubuntu:** 20.04 LTS or later
+* **RHEL/CentOS:** 8 or later
+* **Debian:** 10 (Buster) or later
+* **Fedora:** 32 or later
+
+.. note::
+   For older Linux distributions (e.g., RHEL 7, Ubuntu 16.04, Ubuntu 18.04), you will need to build CausalML from source. See **Install from source** below.
+
+**macOS and Windows:** All recent versions are supported.
+
 Install using ``conda``
 -----------------------
 

pyproject.toml

@@ -1,6 +1,6 @@
 [project]
 name = "causalml"
-version = "0.15.6"
+version = "0.16.0"
 description = "Python Package for Uplift Modeling and Causal Inference with Machine Learning Algorithms"
 readme = { file = "README.md", content-type = "text/markdown" }
 
@@ -26,7 +26,7 @@ dependencies = [
     "forestci==0.6",
     "pathos==0.2.9",
     "numpy>=1.25.2",
-    "scipy>=1.16.0,<1.17.0",  # Pin to versions with manylinux2014 wheels (1.17.0+ requires manylinux_2_27)
+    "scipy>=1.16.0",
     "matplotlib",
     "pandas>=0.24.1",
     "scikit-learn>=1.6.0",
@@ -71,7 +71,7 @@ homepage = "https://github.com/uber/causalml"
 [tool.cibuildwheel]
 build = ["cp311-*", "cp312-*"]
 build-verbosity = 1
-manylinux-x86_64-image = "manylinux2014"
-manylinux-aarch64-image = "manylinux2014"
+manylinux-x86_64-image = "manylinux_2_28"
+manylinux-aarch64-image = "manylinux_2_28"
 # Skip 32-bit builds
 skip = ["*-win32", "*-manylinux_i686", "*-musllinux*"]