diff --git a/requirements_pinned.txt b/requirements_pinned.txt
--- a/requirements_pinned.txt
+++ b/requirements_pinned.txt
@@ -22,4 +22,5 @@ scandir==1.10.0
 setproctitle==1.1.10
 tempita==0.5.2
 testpath==0.4.4
+transaction==2.4.0
 vine==1.3.0