diff --git a/requirements.txt b/requirements.txt
index db768e8..d733360 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -36,7 +36,7 @@ python-dateutil==2.7.3    # via matplotlib, pandas
 pytz==2018.5
 requests==2.19.1
 scipy==1.1.0
-six==1.11.0               # via cryptography, cycler, matplotlib, more-itertools, patsy, pytdx, pytest, python-dateutil
+six==1.12.0               # via cryptography, cycler, matplotlib, more-itertools, patsy, pytdx, pytest, python-dateutil
 statsmodels==0.9.0
 ta-lib==0.4.17
 tornado==5.1.1