diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index f9a95c9f..656c71c9 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -11,10 +11,10 @@ on:
 jobs:
   unit_tests:
     name: Unit Tests
-    runs-on: ubuntu-20.04
+    runs-on: ubuntu-22.04
     strategy:
       matrix:
-        python-version: ['3.7', '3.8', '3.9', '3.10', '3.11']
+        python-version: ['3.7', '3.8', '3.9', '3.10', '3.11', '3.12']
 
     steps:
     - name: Checkout
@@ -36,10 +36,13 @@ jobs:
     - name: Install pip dependencies
       run: python -m pip install flake8 pytest
 
+    - name: Run flake8
+      run: flake8 --ignore=E501,E266 pycdlib tools/*
+
     - name: Build patched cdrkit
       run: |
         pushd vendor
-        tar -xvf cdrkit-1.1.11-fedora29-patched.tar.gz
+        tar -xvf cdrkit-1.1.11-fedora40-patched.tar.gz
         pushd cdrkit-1.1.11
         mkdir build
         pushd build
@@ -49,9 +52,6 @@ jobs:
         popd
         popd
 
-    - name: Run flake8
-      run: flake8 --ignore=E501,E266 pycdlib tools/*
-
     - name: Patch pycdlib-genisoimage for python version
       run: sed -i -e '0,/python3/s//python/' tools/pycdlib-genisoimage
 
diff --git a/vendor/README b/vendor/README
index b1ef5de6..aacd06fe 100644
--- a/vendor/README
+++ b/vendor/README
@@ -1,6 +1,20 @@
 This directory contains vendored files stored in
 Git-LFS (https://git-lfs.github.com/).  In particular:
 
+- cdrkit-1.1.11-fedora40-patched.tar.gz
+  A vendored version of cdrkit (and more specifically, genisoimage) used to
+  run the tests.  We vendor this because the different versions of genisoimage
+  actually put things in different places on the ISO, and this messes with the
+  tests checking where things are in the ISO.  This doesn't mean that pycdlib
+  can only open ISOs from genisoimage; it just means the tests expect that
+  particular layout.  This file was created by downloading the cdrkit source
+  RPM from koji (https://kojipkgs.fedoraproject.org//packages/cdrkit/1.1.11/54.fc40/src/cdrkit-1.1.11-54.fc40.src.rpm,
+  though that URI may not exist anymore).  The package was then installed
+  (rpm -ivh /path/to/*.src.rpm), and then the original source tarball with
+  patches was prepared (rpmbuild -bp cdrkit.spec).  The "icedax" directory was
+  then removed, as it is not required and needs additional dependencies.  It was
+  then tarred back up.
+
 - cdrkit-1.1.11-fedora29-patched.tar.gz
   A vendored version of cdrkit (and more specifically, genisoimage) used to
   run the tests.  We vendor this because the different versions of genisoimage
@@ -14,4 +28,3 @@ Git-LFS (https://git-lfs.github.com/).  In particular:
   exploded (tar -xvf ~/rpmbuild/cdrkit-1.1.11.tar.gz), and then the patches
   from the source RPM were applied in order.  The "icedax" directory was also
   removed from CMakeLists.txt After all of that, it was tarred back up.
-
diff --git a/vendor/cdrkit-1.1.11-fedora40-patched.tar.gz b/vendor/cdrkit-1.1.11-fedora40-patched.tar.gz
new file mode 100644
index 00000000..1c1b8ca5
--- /dev/null
+++ b/vendor/cdrkit-1.1.11-fedora40-patched.tar.gz
@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:262d302e31083fdf4644ba284aa9f9b119c9dd0ef087523e46813cf215e9b3be
+size 1928440