diff --git a/tox.ini b/tox.ini
index 6b645c2b..03f4bb66 100644
--- a/tox.ini
+++ b/tox.ini
@@ -15,7 +15,7 @@ deps =
   pytest-env >= 0.6.2, < 1.0
   requests >= 2.22.0, < 3.0
   requests-mock >= 1.6.0, < 2.0
-  toml >= 0.10
+  toml >= 0.10, < 0.11
   gevent-websocket
   bottle >= 0.12
 commands =