diff --git a/CONTRIBUTING.rst b/CONTRIBUTING.rst
index 12e2925..9a73738 100644
--- a/CONTRIBUTING.rst
+++ b/CONTRIBUTING.rst
@@ -9,14 +9,14 @@ Contributor guidelines
 If you would like to contribute to the development of OpenStack, you must
 follow the steps in this page:
 
-   http://docs.openstack.org/infra/manual/developers.html
+   https://docs.openstack.org/infra/manual/developers.html
 
 If you already have a good understanding of how the system works and your
 OpenStack accounts are set up, you can skip to the development workflow
 section of this documentation to learn how changes to OpenStack should be
 submitted for review via the Gerrit tool:
 
-   http://docs.openstack.org/infra/manual/developers.html#development-workflow
+   https://docs.openstack.org/infra/manual/developers.html#development-workflow
 
 Filing bugs or issues
 ---------------------
@@ -36,6 +36,6 @@ Submitting code
 ---------------
 
 Changes to the project should be submitted for review via the Gerrit tool, following
-the workflow documented at: "http://docs.openstack.org/infra/manual/developers.html#development-workflow"
+the workflow documented at: "https://docs.openstack.org/infra/manual/developers.html#development-workflow"
 
 Pull requests submitted through GitHub will be ignored and closed without regard.
diff --git a/doc/requirements.txt b/doc/requirements.txt
index f2f684b..f8369f8 100644
--- a/doc/requirements.txt
+++ b/doc/requirements.txt
@@ -2,7 +2,7 @@
 # of appearance. Changing the order has an impact on the overall integration
 # process, which may cause wedges in the gate later.
 
-sphinx!=1.6.6,!=1.6.7,>=1.6.2 # BSD
+sphinx>=1.8.0,!=2.1.0;python_version>='3.4' # BSD
 openstackdocstheme>=1.18.1  # Apache-2.0
 # releasenotes
 reno>=2.5.0 # Apache-2.0
diff --git a/tox.ini b/tox.ini
index f55094b..3acbde6 100644
--- a/tox.ini
+++ b/tox.ini
@@ -27,13 +27,16 @@ deps = -r{toxinidir}/doc/requirements.txt
 commands =
   bash -c "rm -rf doc/build"
   doc8 doc
-  sphinx-build -b html doc/source doc/build/html
+  sphinx-build --keep-going -b html doc/source doc/build/html
 
 [doc8]
 extensions = .rst
 
 [testenv:releasenotes]
 basepython = python3
+whitelist_externals =
+  rm
 deps = {[testenv:docs]deps}
 commands =
-    sphinx-build -a -E -W -d releasenotes/build/doctrees -b html releasenotes/source releasenotes/build/html
+  rm -rf releasenotes/build
+  sphinx-build -a -E -W -d releasenotes/build/doctrees --keep-going -b html releasenotes/source releasenotes/build/html