diff --git a/Makefile b/Makefile
index aa87433f..cd9953bd 100644
--- a/Makefile
+++ b/Makefile
@@ -121,7 +121,7 @@ docs: mkdocs uml ## Generate documentation and UML
 
 .PHONY: mkdocs
 mkdocs: install $(MKDOCS_INDEX)
-$(MKDOCS_INDEX): mkdocs.yml docs/*.md
+$(MKDOCS_INDEX): docs/requirements.txt mkdocs.yml docs/*.md
 	@ mkdir -p docs/about
 	@ cd docs && ln -sf ../README.md index.md
 	@ cd docs/about && ln -sf ../../CHANGELOG.md changelog.md
@@ -129,6 +129,10 @@ $(MKDOCS_INDEX): mkdocs.yml docs/*.md
 	@ cd docs/about && ln -sf ../../LICENSE.md license.md
 	poetry run mkdocs build --clean --strict
 
+# Workaround: https://github.com/rtfd/readthedocs.org/issues/5090
+docs/requirements.txt: poetry.lock
+	poetry run pip freeze | grep mkdocs > $@
+
 .PHONY: uml
 uml: install docs/*.png
 docs/*.png: $(MODULES)
diff --git a/docs/requirements.txt b/docs/requirements.txt
new file mode 100644
index 00000000..591f7c09
--- /dev/null
+++ b/docs/requirements.txt
@@ -0,0 +1 @@
+mkdocs==1.0.4