diff --git a/core/modules/book/book.install b/core/modules/book/book.install
index bdc4a28..7c0893e 100644
--- a/core/modules/book/book.install
+++ b/core/modules/book/book.install
@@ -96,6 +96,6 @@ function book_update_8000() {
   update_variables_to_config('book.settings', array(
     'book_allowed_types' => 'allowed_types',
     'book_child_type' => 'child_type',
-    'book_block_mode' => 'block_mode',
+    'book_block_mode' => 'block.navigation.mode',
   ));
 }