diff --git a/pyproject.toml b/pyproject.toml
index cca107c0..80e7fe37 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -28,6 +28,7 @@ classifiers = [
 ]
 urls = {Homepage = "https://radicale.org/"}
 requires-python = ">=3.9.0"
+# Hint: if bcyrpt < 5.0.0 is used, passlib(libpass) dependency can be downgraded/reverted by: sed -i 's|libpass[^"]*|passlib|' pyproject.toml
 dependencies = [
     "defusedxml",
     "libpass>=1.9.3",
diff --git a/setup.py.legacy b/setup.py.legacy
index 50830dad..27957903 100644
--- a/setup.py.legacy
+++ b/setup.py.legacy
@@ -36,6 +36,7 @@ web_files = ["web/internal_data/css/icon.png",
              "web/internal_data/fn.js",
              "web/internal_data/index.html"]
 
+# Hint: if bcyrpt < 5.0.0 is used, passlib(libpass) dependency can be downgraded/reverted by: sed -i 's|libpass[^"]*|passlib|' setup.py.legacy
 install_requires = ["defusedxml", "libpass>=1.9.3", "vobject>=0.9.6",
                     "pika>=1.1.0",
                     "requests",