diff --git a/external/book b/external/book
index da1615146f1c460b2602c69a9512d656d4a85baf..fb35160314253a54bb3022f28e7623e6c2a3b238 160000
--- a/external/book
+++ b/external/book
@@ -1 +1 @@
-Subproject commit da1615146f1c460b2602c69a9512d656d4a85baf
+Subproject commit fb35160314253a54bb3022f28e7623e6c2a3b238