diff --git a/tox.ini b/tox.ini
index 13f5317b82..2e79a80c4d 100644
--- a/tox.ini
+++ b/tox.ini
@@ -1,14 +1,14 @@
 [tox]
-minversion = 2.0
+minversion = 3.1.0
 skipsdist = True
 envlist = py{36,37},pep8
+ignore_basepython_conflict=true
 
 [testenv]
 basepython = python3
 deps = -r{toxinidir}/test-requirements.txt
        -r{toxinidir}/requirements.txt
        -c{env:UPPER_CONSTRAINTS_FILE:https://opendev.org/openstack/requirements/raw/branch/master/upper-constraints.txt}
-install_command = pip install {opts} {packages}
 usedevelop = True
 setenv = VIRTUAL_ENV={envdir}
          CEILOMETER_TEST_BACKEND={env:CEILOMETER_TEST_BACKEND:none}