diff --git a/lower-constraints.txt b/lower-constraints.txt
index d8513b93a..532b5acbe 100644
--- a/lower-constraints.txt
+++ b/lower-constraints.txt
@@ -134,6 +134,7 @@ simplegeneric==0.8.1
 simplejson==3.5.1
 six==1.10.0
 smmap==0.9.0
+Sphinx==1.6.2
 sqlalchemy-migrate==0.11.0
 SQLAlchemy==1.0.10
 sqlparse==0.2.2