diff --git a/.circleci/config.yml b/.circleci/config.yml
index 95074c7..91cc289 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -16,48 +16,37 @@ jobs:
       CIRCLE_ARTIFACTS: /tmp/circleci-artifacts
       CIRCLE_TEST_REPORTS: /tmp/circleci-test-results
     docker:
-      - image: circleci/python:3.6.6-stretch
+      - image: cimg/python:3.6.15
     steps:
       - checkout
       - run: mkdir -p $CIRCLE_ARTIFACTS $CIRCLE_TEST_REPORTS
-      - restore_cache:
-          keys:
-            - v1-dep-{{ .Branch }}-
-            - v1-dep-master-
-            - v1-dep-
+      - run: sudo apt-get update
       - run: sudo apt-get install -y pandoc
-      - run: sudo pip install --progress-bar=off .[testing,docs]
+      - run: python --version
+      - run: pip install --upgrade pip setuptools wheel
+      - run: pip --version
+      - run: pip install --progress-bar=off .[testing,docs]
       - run: python setup.py build_sphinx
-      - save_cache:
-          key: v1-dep-{{ .Branch }}-{{ epoch }}
-          paths:
-            - vendor/bundle
-            - ~/virtualenvs
-            - ~/.m2
-            - ~/.ivy2
-            - ~/.bundle
-            - ~/.go_workspace
-            - ~/.gradle
-            - ~/.cache/bower
-      - run: pytest
+      - run: pytest --junitxml=$CIRCLE_TEST_REPORTS/junit.xml
       - store_test_results:
           path: /tmp/circleci-test-results
       - store_artifacts:
           path: /tmp/circleci-artifacts
       - store_artifacts:
           path: /tmp/circleci-test-results
+          destination: tests
       - store_artifacts:
           path: build/sphinx/html
           destination: docs
   test-python-3.7:
     <<: *build-template
     docker:
-      - image: circleci/python:3.7.3-stretch
+      - image: cimg/python:3.7.12
   test-python-3.8:
     <<: *build-template
     docker:
-      - image: circleci/python:3.8.7
+      - image: cimg/python:3.8.12
   test-python-3.9:
     <<: *build-template
     docker:
-      - image: circleci/python:3.9.7-buster
+      - image: cimg/python:3.9.6
diff --git a/pvfactors/report.py b/pvfactors/report.py
index 95f7a6c..01e15da 100644
--- a/pvfactors/report.py
+++ b/pvfactors/report.py
@@ -32,9 +32,8 @@ class ExampleReportBuilder(object):
 
     @staticmethod
     def build(pvarray):
-        """Method that will build the simulation report. Here we're using the
-        previously defined
-        :py:function:`~pvfactors.report.example_fn_build_report`.
+        """Method that will build the simulation report, using
+        :py:func:`~pvfactors.report.example_fn_build_report`.
 
         Parameters
         ----------
diff --git a/pvfactors/run.py b/pvfactors/run.py
index cc14de2..4e2a7a5 100644
--- a/pvfactors/run.py
+++ b/pvfactors/run.py
@@ -265,7 +265,7 @@ def _run_serially(args):
     ----------
     args : tuple
         List of arguments where most will be used in
-        :py:function:`~pvfactors.run.run_timeseries_engine`
+        :py:func:`~pvfactors.run.run_timeseries_engine`
 
     Returns
     -------
diff --git a/setup.py b/setup.py
index b877064..9133b18 100644
--- a/setup.py
+++ b/setup.py
@@ -46,7 +46,7 @@
       install_requires=INSTALL_REQUIRES,
       extras_require={
           'testing': TESTS_REQUIRES,
-          'docs': ['Sphinx', 'sphinx_rtd_theme', 'nbsphinx',
+          'docs': ['Sphinx~=4.0', 'sphinx_rtd_theme', 'nbsphinx',
                    'sphinxcontrib-napoleon', 'sphinxcontrib_github_alt',
                    'ipykernel']
       },