diff --git a/book/external/Nested-Books b/book/external/Nested-Books
index 238ef4c..a77d4a1 160000
--- a/book/external/Nested-Books
+++ b/book/external/Nested-Books
@@ -1 +1 @@
-Subproject commit 238ef4c766207b861d4509a69cedc10340262934
+Subproject commit a77d4a1d5daff219e692bdd09a01ac441ccb5925