diff --git a/doc/requirements.txt b/doc/requirements.txt
index 19dd2e5..b55c8f8 100644
--- a/doc/requirements.txt
+++ b/doc/requirements.txt
@@ -1,5 +1,4 @@
 os-api-ref>=1.6.1 # Apache-2.0
-openstackdocstheme>=1.30.0  # 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
+openstackdocstheme>=2.0.0  # Apache-2.0
+sphinx>=2.0.0,!=2.1.0 # BSD
 reno>=2.11.3 # Apache-2.0
diff --git a/tox.ini b/tox.ini
index ac5fe53..256d2bb 100644
--- a/tox.ini
+++ b/tox.ini
@@ -1,55 +1,51 @@
 [tox]
 envlist = py3,pep8,cover_report
 skipsdist = True
+minversion = 3.1.1
+ignore_basepython_conflict = True
 
 [testenv]
 usedevelop = True
+basepython = python3
 deps =
-  -c{env:UPPER_CONSTRAINTS_FILE:https://releases.openstack.org/constraints/upper/master}
+  -c{env:TOX_CONSTRAINTS_FILE:https://releases.openstack.org/constraints/upper/master}
   -r{toxinidir}/requirements.txt
   -r{toxinidir}/test-requirements.txt
 commands = adjutant-api test {posargs}
 setenv = VIRTUAL_ENV={envdir}
 
 [testenv:pep8]
-basepython = python3
 commands =
     flake8
     doc8
 
 [testenv:cover]
-basepython = python3
 commands =
     coverage run --source='adjutant' .tox/cover/bin/adjutant-api test {posargs}
     coverage html -d cover
     coverage xml -o cover/coverage.xml
 
 [testenv:cover_report]
-basepython = python3
 commands =
     coverage run --source='.' .tox/cover_report/bin/adjutant-api test {posargs}
     coverage report --include adjutant/* -m
 
 [testenv:venv]
-basepython = python3
 commands = {posargs}
 
 [testenv:docs]
-basepython = python3
 deps =
-  -c{env:UPPER_CONSTRAINTS_FILE:https://releases.openstack.org/constraints/upper/master}
+  -c{env:TOX_CONSTRAINTS_FILE:https://releases.openstack.org/constraints/upper/master}
   -r{toxinidir}/doc/requirements.txt
 commands =
     sphinx-build -W -b html -d doc/build/doctrees doc/source doc/build/html
 
 [testenv:api-ref]
-basepython = python3
 deps = {[testenv:docs]deps}
 commands =
     sphinx-build -W -b html -d api-ref/build/doctrees api-ref/source api-ref/build/html
 
 [testenv:releasenotes]
-basepython = python3
 deps = {[testenv:docs]deps}
 commands = sphinx-build -a -E -d releasenotes/build/doctrees -b html releasenotes/source releasenotes/build/html
 
@@ -66,11 +62,9 @@ ignore-path=.tox,*.egg-info,doc/build,releasenotes/build,api-ref/build,.eggs/*/E
 extension=.txt,.rst,.inc
 
 [testenv:black]
-basepython = python3
 commands =
     black -t py36 .
 
 [testenv:black_check]
-basepython = python3
 commands =
     black -t py36 --check .