diff --git a/doc/requirements.txt b/doc/requirements.txt
index cc9054ae..111e1305 100644
--- a/doc/requirements.txt
+++ b/doc/requirements.txt
@@ -2,8 +2,8 @@
 # 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,<2.0.0;python_version=='2.7' # BSD
-sphinx!=1.6.6,!=1.6.7,!=2.1.0,>=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
 openstackdocstheme>=1.20.0 # Apache-2.0
 reno>=2.5.0 # Apache-2.0
 
diff --git a/lower-constraints.txt b/lower-constraints.txt
index 68970847..3644ce58 100644
--- a/lower-constraints.txt
+++ b/lower-constraints.txt
@@ -57,7 +57,7 @@ rfc3986==1.1.0
 six==1.11.0
 smmap2==2.0.3
 snowballstemmer==1.2.1
-Sphinx==1.6.5
+Sphinx==1.8.0
 sphinxcontrib-websupport==1.0.1
 stestr==2.0.0
 stevedore==1.28.0
diff --git a/tox.ini b/tox.ini
index 18a7e4d2..5c633ce1 100644
--- a/tox.ini
+++ b/tox.ini
@@ -26,17 +26,23 @@ commands = {posargs}
 
 [testenv:docs]
 basepython = python3
+whitelist_externals = rm
 deps =
   -c{env:UPPER_CONSTRAINTS_FILE:https://releases.openstack.org/constraints/upper/master}
   -r{toxinidir}/doc/requirements.txt
-commands = sphinx-build -a -E -W -b html doc/source doc/build/html
+commands =
+  rm -fr doc/build
+  sphinx-build -a -E -W --keep-going -b html doc/source doc/build/html
 
 [testenv:releasenotes]
 basepython = python3
+whitelist_externals = rm
 deps =
   -c{env:UPPER_CONSTRAINTS_FILE:https://releases.openstack.org/constraints/upper/master}
   -r{toxinidir}/doc/requirements.txt
-commands = sphinx-build -a -E -W -b html releasenotes/source releasenotes/build/html
+commands =
+  rm -rf releasenotes/build
+  sphinx-build -a -E -W --keep-going -b html releasenotes/source releasenotes/build/html
 
 [testenv:cover]
 basepython = python3