diff --git a/requirements.txt b/requirements.txt
index 723f7c8..3cc090b 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -41,7 +41,7 @@ python-dateutil==1.5
 pytz==2019.3
 requests==2.20.0
 sip==4.19.8
-six==1.12.0
+six==1.15.0
 snowballstemmer==2.0.0
 Sphinx==2.2.2
 sphinxcontrib-applehelp==1.0.1