diff --git a/doc/requirements.txt b/doc/requirements.txt
index 2faa201c..1264adee 100644
--- a/doc/requirements.txt
+++ b/doc/requirements.txt
@@ -3,8 +3,8 @@
 # process, which may cause wedges in the gate later.
 # These are needed for docs generation
 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
 reno>=2.5.0 # Apache-2.0
 
 mock>=2.0.0 # BSD
diff --git a/tox.ini b/tox.ini
index 3b30c311..a36ccb72 100644
--- a/tox.ini
+++ b/tox.ini
@@ -23,14 +23,20 @@ commands = {posargs}
 commands = python setup.py test --coverage --coverage-package-name=oslo_versionedobjects --testr-args='{posargs}'
 
 [testenv:docs]
+whitelist_externals = rm
 deps =
   -c{env:UPPER_CONSTRAINTS_FILE:https://git.openstack.org/cgit/openstack/requirements/plain/upper-constraints.txt}
   -r{toxinidir}/doc/requirements.txt
-commands = sphinx-build -W -b html doc/source doc/build/html
+commands =
+  rm -fr doc/build
+  sphinx-build -W --keep-going -b html doc/source doc/build/html
 
 [testenv:releasenotes]
+whitelist_externals = rm
 deps = {[testenv:docs]deps}
-commands = sphinx-build -a -E -W -d releasenotes/build/doctrees -b html releasenotes/source releasenotes/build/html
+commands =
+  rm -rf releasenotes/build
+  sphinx-build -a -E -W -d releasenotes/build/doctrees --keep-going -b html releasenotes/source releasenotes/build/html
 
 [testenv:lower-constraints]
 deps =