diff --git a/tox.ini b/tox.ini
index c397c8c..01ee4cf 100644
--- a/tox.ini
+++ b/tox.ini
@@ -1,5 +1,5 @@
 [tox]
-minversion = 3.1.1
+minversion = 3.18.0
 envlist = py36,py38,docs,pep8
 skipsdist = True
 ignore_basepython_conflict = True
@@ -42,7 +42,7 @@ commands =
 
 [testenv:pdf-docs]
 deps = {[testenv:docs]deps}
-whitelist_externals = make
+allowlist_externals = make
 commands =
     sphinx-build -b latex doc/source doc/build/pdf
     make -C doc/build/pdf