diff --git a/tox.ini b/tox.ini
index 9f3dd8fc9..e1c9b6db5 100644
--- a/tox.ini
+++ b/tox.ini
@@ -1,8 +1,8 @@
 [tox]
-envlist = py27,py34
+envlist = py{27,35,36,37}
 
 [testenv]
-changedir=test_project
+changedir = test_project
 commands =
     python ../tests.py
     coverage run --source modoboa manage.py test modoboa.core modoboa.lib modoboa.admin modoboa.limits modoboa.relaydomains
@@ -19,7 +19,7 @@ setenv =
     DB=SQLITE
 
 [testenv:serve]
-changedir=test_project
+changedir = test_project
 whitelist_externals =
     rm
 commands =