diff --git a/tox.ini b/tox.ini
index 4a956b0f1..71b1a4193 100644
--- a/tox.ini
+++ b/tox.ini
@@ -1,5 +1,5 @@
 [tox]
-minversion = 3.2.0
+minversion = 3.18.0
 envlist = pep8,py37,py36
 skipsdist = True
 
@@ -68,7 +68,7 @@ commands =
   sphinx-build -a -E -W --keep-going -b html doc/source doc/build/html
 
 [testenv:pdf-docs]
-whitelist_externals = make
+allowlist_externals = make
 description =
   Build PDF documentation.
 envdir = {toxworkdir}/docs