diff --git a/tox.ini b/tox.ini
index 74ebb4ef5e..fedefab794 100644
--- a/tox.ini
+++ b/tox.ini
@@ -31,13 +31,9 @@ commands =
     python tools/custom_guidelines.py --exclude heat/engine/resources/aws
 
 [testenv:venv]
-# Note: infra doesn't support to use of constraints for this target.
-install_command = pip install -U --force-reinstall {opts} {packages}
 commands = {posargs}
 
 [testenv:cover]
-# Note: infra doesn't support to use of constraints for this target.
-install_command = pip install -U --force-reinstall {opts} {packages}
 commands =
   python setup.py testr --coverage --testr-args='^(?!heat_integrationtests){posargs}'
 
@@ -51,16 +47,11 @@ commands = python setup.py build_sphinx
 # This environment is called from CI scripts to test and publish
 # the API Ref to developer.openstack.org.
 #
-# NOTE(sdague): this target does not use constraints because
-# upstream infra does not yet support it. Once that's fixed, we can
-# drop the install_command.
-#
 # we do not used -W here because we are doing some slightly tricky
 # things to build a single page document, and as such, we are ok
 # ignoring the duplicate stanzas warning.
 whitelist_externals = bash
                       rm
-install_command = pip install -U --force-reinstall {opts} {packages}
 commands =
   rm -rf api-ref/build
   sphinx-build -b html -d api-ref/build/doctrees api-ref/source api-ref/build/html
@@ -86,13 +77,7 @@ local-check-factory = heat.hacking.checks.factory
 commands = oslo_debug_helper {posargs}
 
 [testenv:releasenotes]
-# Note: infra doesn't support to use of constraints for this target.
-install_command = pip install -U --force-reinstall {opts} {packages}
 commands = sphinx-build -a -E -W -d releasenotes/build/doctrees -b html releasenotes/source releasenotes/build/html
 
 [testenv:install-guide]
-# NOTE(jaegerandi): this target does not use constraints because
-# upstream infra does not yet support it. Once that's fixed, we can
-# drop the install_command.
-install_command = pip install -U --force-reinstall {opts} {packages}
 commands = sphinx-build -a -E -W -d install-guide/build/doctrees -b html install-guide/source install-guide/build/html