diff --git a/requirements.txt b/requirements.txt
index 152d549..cb88cbc 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,5 +1,5 @@
-gevent==1.4.0
-holster==2.0.0
-requests==2.20.1
-six==1.11.0
-websocket-client==0.44.0
+gevent>=1.3.0,<2
+holster>=2.0.0,<3
+requests>=2.20.1,<3
+six>=1.11.0,<2
+websocket-client>=0.44.0,<1