diff --git a/external/book b/external/book
index ffcf5e451e3830dfec33061295f8705c4bc43a9d..db95d22564bd94d4beaf4439f7c9b456e7510c6b 160000
--- a/external/book
+++ b/external/book
@@ -1 +1 @@
-Subproject commit ffcf5e451e3830dfec33061295f8705c4bc43a9d
+Subproject commit db95d22564bd94d4beaf4439f7c9b456e7510c6b