diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 2019b17..3aa6b46 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -19,10 +19,10 @@ jobs:
       - uses: actions/checkout@v2.3.4
         with:
           submodules: recursive
-      - name: Set up Python 3.7
+      - name: Set up Python 3.8
         uses: actions/setup-python@v2.2.1
         with:
-          python-version: 3.7
+          python-version: "3.8"
       - name: Install tox
         run: pip install tox
       - name: Lint
@@ -39,10 +39,10 @@ jobs:
       - uses: actions/checkout@v2.3.4
         with:
           submodules: recursive
-      - name: Set up Python 3.7
+      - name: Set up Python 3.8
         uses: actions/setup-python@v2.2.1
         with:
-          python-version: 3.7
+          python-version: 3.8
       - name: Install tox and upgrade setuptools and pip
         run: pip install --upgrade tox setuptools pip
       - name: Run tox -e ${{ matrix.tox_env }}
@@ -53,20 +53,19 @@ jobs:
     strategy:
       matrix:
         python-version:
-          - "3.7"
           - "3.8"
           - "3.9"
           - "3.10"
           - "3.11"
-          - "pypy-3.7"
-          - "pypy-3.8"
+          - "3.12"
           - "pypy-3.9"
+          - "pypy-3.10"
         os: ["ubuntu-latest"]
         include:
           - os: "macos-latest"
-            python-version: 3.7
+            python-version: "3.8"
           - os: "windows-latest"
-            python-version: 3.7
+            python-version: "3.8"
     steps:
       - uses: actions/checkout@v2.3.4
         with:
diff --git a/.readthedocs.yml b/.readthedocs.yml
index 20eb6cd..c6c9f8e 100644
--- a/.readthedocs.yml
+++ b/.readthedocs.yml
@@ -1,15 +1,22 @@
 version: 2
 formats: []  # Do not build epub and pdf
 
-# This adds mambaforge for the installation
-build:
-  os: "ubuntu-20.04"
-  tools:
-    python: "mambaforge-4.10"
-
 python:
   install:
-    - method: pip
-      path: .
-conda:
-  environment: docs/conda-environment.yml
\ No newline at end of file
+    - requirements: "requirements-docs.txt"
+    - method: "pip"
+      path: "."
+
+sphinx:
+  configuration: docs/conf.py
+
+build:
+  os: "ubuntu-22.04"
+  tools:
+    python: "3"
+  apt_packages:
+    - python3
+    - python3-pip
+    - cmake
+    - git
+    - googletest
diff --git a/CHANGELOG.rst b/CHANGELOG.rst
index 8beb14c..aea6e2e 100644
--- a/CHANGELOG.rst
+++ b/CHANGELOG.rst
@@ -9,11 +9,19 @@ Changelog
 
 version 0.3.0-dev
 -----------------
++ Python 3.12 support was added. Python 3.7 support was dropped as it is end
+  of life.
 + Enabled installation on BSD
-+ Update embedded zlib-ng version to 2.1.2. This comes with some speed
-  improvements and changes with regards to the compression levels. For full
++ Update embedded zlib-ng version to 2.1.5. This comes with some speed
+  improvements and changes with regards to the compression levels. Also
+  several bugs were fixed. For full
   details checkout the `zlib-ng 2.1.2 release notes
-  <https://github.com/zlib-ng/zlib-ng/releases/tag/2.1.2>`_.
+  <https://github.com/zlib-ng/zlib-ng/releases/tag/2.1.2>`_ as well as
+  those for the bugfix releases `2.1.3
+  <https://github.com/zlib-ng/zlib-ng/releases/tag/2.1.3>`_,
+  `2.1.4 <https://github.com/zlib-ng/zlib-ng/releases/tag/2.1.4>`_ and
+  `2.1.5 <https://github.com/zlib-ng/zlib-ng/releases/tag/2.1.5>`_.
+
 
 version 0.2.0
 -----------------
diff --git a/setup.py b/setup.py
index 413853b..d349300 100644
--- a/setup.py
+++ b/setup.py
@@ -142,11 +142,11 @@ def build_zlib_ng():
     classifiers=[
         "Programming Language :: Python :: 3 :: Only",
         "Programming Language :: Python :: 3",
-        "Programming Language :: Python :: 3.7",
         "Programming Language :: Python :: 3.8",
         "Programming Language :: Python :: 3.9",
         "Programming Language :: Python :: 3.10",
         "Programming Language :: Python :: 3.11",
+        "Programming Language :: Python :: 3.12",
         "Programming Language :: Python :: Implementation :: CPython",
         "Programming Language :: Python :: Implementation :: PyPy",
         "Programming Language :: C",
@@ -157,6 +157,6 @@ def build_zlib_ng():
         "Operating System :: MacOS",
         "Operating System :: Microsoft :: Windows",
     ],
-    python_requires=">=3.7",  # uses METH_FASTCALL
+    python_requires=">=3.8",  # Earliest version still tested.
     ext_modules=EXTENSIONS
 )
diff --git a/src/zlib_ng/zlib-ng b/src/zlib_ng/zlib-ng
index f75c685..2bc6688 160000
--- a/src/zlib_ng/zlib-ng
+++ b/src/zlib_ng/zlib-ng
@@ -1 +1 @@
-Subproject commit f75c6856c32a0ade1f33e266fb370bac92d15fac
+Subproject commit 2bc66887ddc0c50776811a27be68e34430d665e1