diff --git a/tools/pip-requires b/tools/pip-requires
index e7086300c..88b00d27d 100644
--- a/tools/pip-requires
+++ b/tools/pip-requires
@@ -1,4 +1,4 @@
 argparse
-prettytable
+prettytable>=0.6,<0.8
 requests>=0.8
-simplejson
+simplejson>=2.0.9