diff --git a/requirements.txt b/requirements.txt
index 7b3ce62..0e7fa99 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,2 +1,2 @@
-colorama==0.3.9
-six==1.11.0
+colorama>=0.3.9,<2
+six~=1.11