diff --git a/optional-requirements.txt b/optional-requirements.txt
index dd4f9878..ef0b2fca 100644
--- a/optional-requirements.txt
+++ b/optional-requirements.txt
@@ -10,7 +10,7 @@ pyasn1>=0.1.9
 PyDrive>=1.3.1
 PyYAML>=3.12
 rsa==3.4.2
-six==1.10.0
+six>=1.10.0
 
 # goodreads
 goodreads>=0.3.2