diff --git a/requirements.txt b/requirements.txt
index d821c3b..29c9200 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -4,3 +4,4 @@ WebOb>=1.6.0 # MIT
 requests>=2.10.0 # Apache-2.0
 netaddr>=0.7.13,!=0.7.16  # BSD
 oslo.concurrency>=3.8.0 # Apache-2.0
+oslo.serialization>=2.18.0,!=2.19.1 # Apache-2.0