diff --git a/docs/requirements.txt b/docs/requirements.txt
index fcb4fd0faf..9c409bc241 100644
--- a/docs/requirements.txt
+++ b/docs/requirements.txt
@@ -1,13 +1,26 @@
+## The following requirements were added by pip freeze:
 alabaster==0.7.8
 Babel==2.3.4
+certifi==2018.4.16
+chardet==3.0.4
 docutils==0.12
+idna==2.6
 imagesize==0.7.1
 Jinja2==2.8
 MarkupSafe==0.23
-Pygments==2.1.3
+packaging==17.1
+pdfrw==0.4
+Pillow==5.1.0
+Pygments==2.2.0
+pyparsing==2.2.0
 pytz==2016.4
+reportlab==3.4.0
+requests==2.18.4
+rst2pdf==0.93
 six==1.10.0
 snowballstemmer==1.2.1
-Sphinx==1.4.4
+Sphinx==1.7.4
 sphinx-rtd-theme==0.1.9
-rst2pdf==0.93
+sphinxcontrib-websupport==1.0.1
+typing==3.6.4
+urllib3==1.22