diff --git a/requirements-dev.txt b/requirements-dev.txt
index d7a04ed..0561d0a 100644
--- a/requirements-dev.txt
+++ b/requirements-dev.txt
@@ -1,4 +1,5 @@
 --requirement requirements-test.txt
 ipython
 pipenv
+# The bump-version script requires at least version 3 of semver.
 semver>=3