diff --git a/.github/workflows/wheels.yml b/.github/workflows/wheels.yml
index cbf0b99..1b238ac 100644
--- a/.github/workflows/wheels.yml
+++ b/.github/workflows/wheels.yml
@@ -16,7 +16,7 @@ jobs:
             arch: "x86_64"
           - os: windows-2022
             arch: "AMD64"
-          - os: macos-13
+          - os: macos-12
             arch: "x86_64"
           - os: macos-14
             arch: "arm64"
@@ -25,7 +25,7 @@ jobs:
     - uses: actions/checkout@v4
 
     - name: Build wheels
-      uses: pypa/cibuildwheel@v2.16.5
+      uses: pypa/cibuildwheel@v2.18.1
       env:
         CIBW_ARCHS: "${{ matrix.arch }}"
 
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 8048838..781835e 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -14,7 +14,7 @@ include(FetchContent)
 FetchContent_Declare(
   gemmi
   GIT_REPOSITORY https://github.com/project-gemmi/gemmi.git
-  GIT_TAG        v0.6.5
+  GIT_TAG        v0.6.6
   #GIT_TAG        master
   GIT_SHALLOW    TRUE
 )
diff --git a/README.md b/README.md
index 0d03136..a8cbbdb 100644
--- a/README.md
+++ b/README.md
@@ -10,9 +10,11 @@ because, unlike the module, it does not depend on Python version.
 
 ### notes for myself -- how to make wheels after gemmi release
 
-* update `GIT_TAG` in CMakeLists.txt and `version` in pyproject.toml
-* (optionally) update version of cibuildwheel in .github/workflows/wheels.yml
-  and scikit-build-core in pyproject.toml
+* update:
+  * `GIT_TAG` in CMakeLists.txt
+  * `version` in pyproject.toml
+  * scikit-build-core version in pyproject.toml (optional)
+  * cibuildwheel version in .github/workflows/wheels.yml (optional)
 * test locally with `pip wheel .`
 * make source distribution of this repo: `python -m build --sdist`
 * git push changes to build wheels in [GitHub Actions][1]
diff --git a/pyproject.toml b/pyproject.toml
index 37217ac..926f8d8 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -1,10 +1,10 @@
 [build-system]
-requires = ["scikit-build-core~=0.8.0"]
+requires = ["scikit-build-core~=0.9.0"]
 build-backend = "scikit_build_core.build"
 
 [project]
 name = "gemmi-program"
-version = "0.6.5"
+version = "0.6.6"
 requires-python = ">=3.8"
 description="gemmi (program executable only)"
 readme = "README.md"