diff --git a/scripts/xos_dev_reqs.txt b/scripts/xos_dev_reqs.txt
index 4a4abdb..ff3c3ac 100644
--- a/scripts/xos_dev_reqs.txt
+++ b/scripts/xos_dev_reqs.txt
@@ -12,7 +12,8 @@
 netaddr==0.7.19
 networkx==1.11
 nose2==0.7.4
-plyxproto==3.1.0
+ply==3.11
+plyxproto==4.0.0
 pykwalify==1.6.1
 requests-mock==1.5.0
 tosca-parser==0.9.0