diff --git a/tox.ini b/tox.ini
index 8f2829d..284b401 100644
--- a/tox.ini
+++ b/tox.ini
@@ -1,5 +1,5 @@
 [tox]
-minversion = 3.9.0
+minversion = 3.18.0
 envlist = py3,pep8
 skipsdist = True
 ignore_basepython_conflict=true
@@ -56,7 +56,7 @@ commands = sphinx-build -W -b html doc/source doc/build/html
 
 [testenv:pdf-docs]
 deps = {[testenv:docs]deps}
-whitelist_externals = make
+allowlist_externals = make
 commands =
   sphinx-build -W -b latex doc/source doc/build/pdf
   make -C doc/build/pdf