diff --git a/CHANGELOG.md b/CHANGELOG.md
index 177523b..27b9e90 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -9,6 +9,32 @@ release `MAJOR.MINOR.PATCH` increments
 - `MINOR` on backwards-compatible feature additions,
 - `PATCH` on backwards-compatible bug fixes.
 
+## [1.1.0] - 2026-05-10
+
+Binary matrix expanded to four CPython versions on both supported
+platforms.
+
+### Added
+
+- Pre-compiled Linux x86_64 binaries for **CPython 3.10, 3.11, 3.13**
+  (`sem_core12.cpython-3{10,11,13}-x86_64-linux-gnu.so`).  Built in
+  isolated conda-forge environments with conda-forge gcc, same
+  OpenMP and optimisation flags as the cp312 binary.
+- Pre-compiled Windows AMD64 binaries for **CPython 3.10, 3.11, 3.13**
+  (`sem_core12.cp3{10,11,13}-win_amd64.pyd`).  Built with MSVC v14.50
+  against the matching CPython installed via `winget`.
+
+### Verified
+
+- All eight binaries (4 Linux + 4 Windows) produce identical numerical
+  output for the same fixed-seed input on `batch_max_similarity`.
+
+### Compatibility notes
+
+- macOS is still not provided in this release.  Contact
+  `sales@sevana.biz` if you need a macOS build.
+- numpy requirement unchanged: `numpy >= 1.23`.
+
 ## [1.0.0] - 2026-05-09
 
 First public release.
diff --git a/README.md b/README.md
index bdeb839..1784174 100644
--- a/README.md
+++ b/README.md
@@ -44,32 +44,42 @@ exercise these three jobs against well-known baselines.
 
 ## Contents
 
-- `sem_cython12/sem_core12.cpython-312-x86_64-linux-gnu.so` -
-  compiled extension (Linux, CPython 3.12, x86_64).
-- `sem_cython12/sem_core12.cp312-win_amd64.pyd` -
-  compiled extension (Windows, CPython 3.12, AMD64).
+- `sem_cython12/sem_core12.cpython-3{10,11,12,13}-x86_64-linux-gnu.so` -
+  compiled extensions (Linux, x86_64) for CPython 3.10 / 3.11 / 3.12 / 3.13.
+- `sem_cython12/sem_core12.cp3{10,11,12,13}-win_amd64.pyd` -
+  compiled extensions (Windows, AMD64) for CPython 3.10 / 3.11 / 3.12 / 3.13.
 - `sem_cython12/wrapper.py` - Python API.
 - `sem_cython12/__init__.py` - package entry.
 
+Python's import system selects the correct binary for the running
+interpreter automatically — install the whole package and the right
+`.so` / `.pyd` is picked up by ABI tag.
+
 ## Compatibility
 
-| Platform        | Architecture | Python    | Runtime requirements        |
-|-----------------|--------------|-----------|-----------------------------|
-| Linux           | x86_64       | CPython 3.12 | glibc >= 2.31, libgomp   |
-| Windows 10/11   | AMD64        | CPython 3.12 | vcomp (ships with Windows) |
-| macOS           | -            | -         | not provided (contact sales@sevana.biz) |
+| Platform        | Architecture | Python                 | Runtime requirements        |
+|-----------------|--------------|------------------------|-----------------------------|
+| Linux           | x86_64       | CPython 3.10/3.11/3.12/3.13 | glibc >= 2.31, libgomp   |
+| Windows 10/11   | AMD64        | CPython 3.10/3.11/3.12/3.13 | vcomp (ships with Windows) |
+| macOS           | -            | -                      | not provided (contact sales@sevana.biz) |
 
 Single Python dependency: `numpy >= 1.23` (see `requirements.txt`).
 
 ## How the binaries were built
 
-- **Linux (`*.so`)**: gcc 13.3, OpenMP via `libgomp`, flags
-  `-O3 -ffast-math -march=native -fopenmp`.
-- **Windows (`*.pyd`)**: MSVC v14.50 (Visual Studio Build Tools 2026),
-  OpenMP via `vcomp`, flags `/O2 /openmp`.
+- **Linux (`*.so`), cp312**: system gcc 13.3 on Ubuntu, OpenMP via
+  `libgomp`, flags `-O3 -ffast-math -march=native -fopenmp`.
+- **Linux (`*.so`), cp310 / cp311 / cp313**: conda-forge gcc inside
+  isolated `python=3.10/3.11/3.13` envs (clean, system-Python-free
+  build), same OpenMP and optimisation flags.
+- **Windows (`*.pyd`), all four versions**: MSVC v14.50 (Visual Studio
+  Build Tools 2026), OpenMP via `vcomp`, flags `/O2 /openmp`. Each
+  built against the matching CPython interpreter installed via
+  `winget`.
 
-Both binaries target CPython 3.12 (cp312) ABI.  No other Python
-version is supported in this release.
+All eight binaries pass the same numerical smoke test
+(`batch_max_similarity` over fixed-seed data) and produce identical
+output to within float64 round-off.
 
 ## Install
 
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