diff --git a/.github/workflows/ci_workflows.yml b/.github/workflows/ci_workflows.yml
index d1b446d..db355e4 100644
--- a/.github/workflows/ci_workflows.yml
+++ b/.github/workflows/ci_workflows.yml
@@ -29,53 +29,41 @@ jobs:
           # Linux - test different Sphinx versions
           - os: ubuntu-latest
             python-version: 3.7
-            toxenv: py37-test-sphinx24
+            toxenv: py37-test-sphinx40
           - os: ubuntu-latest
             python-version: 3.8
-            toxenv: py38-test-sphinx35
-          - os: ubuntu-latest
-            python-version: 3.8
-            toxenv: py38-test-sphinx40
-          - os: ubuntu-latest
-            python-version: 3.9
-            toxenv: py39-test-sphinx41
+            toxenv: py38-test-sphinx53
           - os: ubuntu-latest
             python-version: 3.9
-            toxenv: py39-test-sphinx42
+            toxenv: py39-test-sphinx62
           - os: ubuntu-latest
             python-version: '3.10'
-            toxenv: py310-test-sphinx43-cov-clocale
-          - os: ubuntu-latest
-            python-version: '3.10'
-            toxenv: py310-test-sphinxdev
+            toxenv: py310-test-sphinx70
           - os: ubuntu-latest
             python-version: '3.11'
-            toxenv: py310-test-sphinx53
+            toxenv: py311-test-sphinx71-cov-clocale
           - os: ubuntu-latest
-            python-version: '3.11'
-            toxenv: py310-test-sphinx61
+            python-version: '3.12-dev'
+            toxenv: py312-test-sphinxdev
 
-          # MacOS X - just the oldest, stable, and dev
-          #- os: macos-latest
-          #  python-version: 3.7
-          #  toxenv: py37-test-sphinx24
+          # MacOS X - just the stable and dev
           - os: macos-latest
-            python-version: 3.8
-            toxenv: py38-test-sphinx43-clocale
+            python-version: '3.10'
+            toxenv: py310-test-sphinx71-clocale
           - os: macos-latest
-            python-version: 3.9
-            toxenv: py39-test-sphinxdev
+            python-version: '3.11'
+            toxenv: py311-test-sphinxdev
 
           # Windows - just the oldest, stable, and dev
           - os: windows-latest
             python-version: 3.7
-            toxenv: py37-test-sphinx24
+            toxenv: py37-test-sphinx40
           - os: windows-latest
-            python-version: 3.8
-            toxenv: py38-test-sphinx43
+            python-version: '3.10'
+            toxenv: py310-test-sphinx71
           - os: windows-latest
-            python-version: 3.9
-            toxenv: py39-test-sphinxdev
+            python-version: '3.11'
+            toxenv: py311-test-sphinxdev
 
     steps:
     - uses: actions/checkout@v3
diff --git a/.readthedocs.yml b/.readthedocs.yml
index dcaaaba..93f9723 100644
--- a/.readthedocs.yml
+++ b/.readthedocs.yml
@@ -8,6 +8,9 @@ build:
   os: ubuntu-22.04
   tools:
     python: "3.11"
+  jobs:
+    post_checkout:
+      - git fetch --shallow-since=2023-01-01  || true
 
 sphinx:
   builder: html
@@ -15,6 +18,7 @@ sphinx:
   fail_on_warning: true
 
 python:
+  system_packages: false
   install:
     - method: pip
       path: .
diff --git a/CHANGES.rst b/CHANGES.rst
index 2c321ff..035c19c 100644
--- a/CHANGES.rst
+++ b/CHANGES.rst
@@ -4,6 +4,10 @@ Changes in sphinx-automodapi
 0.16.0 (unreleased)
 -------------------
 
+- Fixed broken inheritance-diagram links due to the smart resolver. [#172]
+
+- Minimum supported Sphinx version is now 4. [#170]
+
 0.15.0 (2023-03-13)
 -------------------
 
diff --git a/setup.cfg b/setup.cfg
index 12774e1..efb9aaa 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -28,6 +28,7 @@ test =
     pytest-cov
     cython
     coverage
+    setuptools;python_version>='3.12'
 rtd =
     # https://github.com/readthedocs/sphinx_rtd_theme/issues/1463
     sphinx<7
diff --git a/tox.ini b/tox.ini
index 7e4c94a..4ec899f 100644
--- a/tox.ini
+++ b/tox.ini
@@ -1,5 +1,5 @@
 [tox]
-envlist = py{37,38,39,310,311}-test-sphinx{24,35,40,41,42,43,53,60,61,dev}{,-cov}{-clocale,}
+envlist = py{37,38,39,310,311,312}-test-sphinx{40,53,62,70,71,dev}{-cov}{-clocale}
 requires = pip >= 18.0
            setuptools >= 30.3.0
 isolated_build = true
@@ -7,17 +7,11 @@ isolated_build = true
 [testenv]
 changedir = .tmp/{envname}
 deps =
-    sphinx24: sphinx==2.4.*
-    sphinx24: Jinja2==3.0.3
-    sphinx35: sphinx==3.5.*
-    sphinx35: Jinja2==3.0.3
     sphinx40: sphinx==4.0.*
-    sphinx41: sphinx==4.1.*
-    sphinx42: sphinx==4.2.*
-    sphinx43: sphinx==4.3.*
     sphinx53: sphinx==5.3.*
-    sphinx60: sphinx==6.0.*
-    sphinx61: sphinx==6.1.*
+    sphinx62: sphinx==6.2.*
+    sphinx70: sphinx==7.0.*
+    sphinx71: sphinx==7.1.*
     sphinxdev: git+https://github.com/sphinx-doc/sphinx.git
 extras =
     test: test