diff --git a/.readthedocs.yml b/.readthedocs.yml
index 95ca143..27561e3 100644
--- a/.readthedocs.yml
+++ b/.readthedocs.yml
@@ -7,7 +7,7 @@ version: 2
 build:
   os: ubuntu-20.04
   tools:
-    python: "3.8"
+    python: "3.9"
 
 sphinx:
   configuration: docs/conf.py
diff --git a/Makefile b/Makefile
index b58d9c1..5668037 100644
--- a/Makefile
+++ b/Makefile
@@ -10,8 +10,8 @@ help:
 clean:  ## Clean build artifacts
 	rm -rf build dist src/${PROJECT}.egg-info .tox
 	rm -rf docs/_build/*
-	find ${PROJECT}/ tests/ -name __pycache__ | xargs rm -rf
-	find ${PROJECT}/ tests/ -name '*.pyc' | xargs rm -rf
+	find src/${PROJECT}/ tests/ -name __pycache__ | xargs rm -rf
+	find src/${PROJECT}/ tests/ -name '*.pyc' | xargs rm -rf
 
 .PHONY: lint
 lint:  ## Lint and black reformat files
diff --git a/requirements-dev.txt b/requirements-dev.txt
index af41ef6..f3e0f6e 100644
--- a/requirements-dev.txt
+++ b/requirements-dev.txt
@@ -13,6 +13,6 @@ wheel==0.41.2
 
 tomli>=1.1.0; python_version < '3.11'
 
-# NOTE(willkg): when we drop support for Python 3.7, we can upgrade these
-Sphinx==5.3.0
-sphinx-rtd-theme==1.0.0
+Sphinx==7.2.6; python_version > "3.8"
+Sphinx==6.2.1; python_version <= "3.8"
+sphinx_rtd_theme==1.3.0