diff --git a/test-requirements.txt b/test-requirements.txt
index 3a1dc427db..be7da6d268 100644
--- a/test-requirements.txt
+++ b/test-requirements.txt
@@ -1,3 +1,3 @@
-sphinx>=1.5.1 # BSD
+sphinx>=1.5.1,!=1.6.1 # BSD
 oslosphinx>=4.7.0 # Apache-2.0
 pbr>=3.0.0 # Apache-2.0
diff --git a/tox.ini b/tox.ini
index 52cd988bd9..17de54d784 100644
--- a/tox.ini
+++ b/tox.ini
@@ -4,7 +4,7 @@ envlist = docs
 skipsdist = True
 
 [testenv]
-install_command = pip install -U {opts} {packages}
+install_command = pip install -c{env:UPPER_CONSTRAINTS_FILE:https://git.openstack.org/cgit/openstack/requirements/plain/upper-constraints.txt} -U {opts} {packages}
 setenv = VIRTUAL_ENV={envdir}
 deps = -r{toxinidir}/test-requirements.txt
 passenv = *_proxy *_PROXY