diff --git a/doc/requirements.txt b/doc/requirements.txt
index 8b11e59..92f8ab6 100644
--- a/doc/requirements.txt
+++ b/doc/requirements.txt
@@ -3,5 +3,5 @@
 # process, which may cause wedges in the gate later.
 
 openstackdocstheme>=1.18.1 # Apache-2.0
-sphinx!=1.6.6,!=1.6.7,>=1.6.2,<2.0.0;python_version=='2.7'  # BSD
-sphinx!=1.6.6,!=1.6.7,>=1.6.2;python_version>='3.4'  # BSD
+sphinx>=1.8.0,<2.0.0;python_version=='2.7' # BSD
+sphinx>=1.8.0,!=2.1.0;python_version>='3.4' # BSD
diff --git a/lower-constraints.txt b/lower-constraints.txt
index ff17a2f..1213f42 100644
--- a/lower-constraints.txt
+++ b/lower-constraints.txt
@@ -69,7 +69,7 @@ rfc3986==0.3.1
 simplejson==3.5.1
 six==1.10.0
 snowballstemmer==1.2.1
-Sphinx==1.6.5
+Sphinx==1.8.0
 sphinxcontrib-websupport==1.0.1
 stevedore==1.20.0
 stestr==2.0.0
diff --git a/tox.ini b/tox.ini
index 8b8c6bd..bb15c12 100644
--- a/tox.ini
+++ b/tox.ini
@@ -51,8 +51,12 @@ commands =
 
 [testenv:docs]
 basepython = python3
+whitelist_externals =
+  rm
 deps = -r{toxinidir}/doc/requirements.txt
-commands = sphinx-build -b html doc/source doc/build/html
+commands =
+  rm -rf doc/build
+  sphinx-build --keep-going -b html doc/source doc/build/html
 
 [flake8]
 ignore = E123,E126,E128,E241,E265,E713,H202,H405,H238