diff --git a/requirements.txt b/requirements.txt
index 2b44c41..f836a27 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -4,12 +4,24 @@
 #
 #    pip-compile --output-file requirements.txt requirements.in
 #
-django-environ==0.4.3
 django==1.11.2
-iso8601==0.1.11           # via lepo
-jsonschema==2.6.0         # via lepo
+    # via
+    #   -r requirements.in
+    #   django-environ
+    #   lepo
+django-environ==0.4.3
+    # via -r requirements.in
+iso8601==0.1.11
+    # via lepo
+jsonschema==2.6.0
+    # via lepo
 lepo==0.0.0
-marshmallow==2.13.5       # via lepo
-pytz==2017.2              # via django
-pyyaml==3.12
-six==1.10.0               # via django-environ
+    # via -r requirements.in
+marshmallow==2.13.5
+    # via lepo
+pytz==2017.2
+    # via django
+pyyaml==5.4
+    # via -r requirements.in
+six==1.10.0
+    # via django-environ