diff --git a/external/book b/external/book
index d233b20945bc22a220ffd05b74dbe47bdae69007..748fa6eeb12d43cc906afb4aeb58273c1835f634 160000
--- a/external/book
+++ b/external/book
@@ -1 +1 @@
-Subproject commit d233b20945bc22a220ffd05b74dbe47bdae69007
+Subproject commit 748fa6eeb12d43cc906afb4aeb58273c1835f634