diff --git a/.github/workflows/deploy.yml b/.github/workflows/deploy.yml
index be0214b5..0c27e53c 100644
--- a/.github/workflows/deploy.yml
+++ b/.github/workflows/deploy.yml
@@ -14,7 +14,7 @@ jobs:
     - name: Install mdbook
       run: |
         mkdir mdbook
-        curl -Lf https://github.com/rust-lang/mdBook/releases/download/v0.4.10/mdbook-v0.4.10-x86_64-unknown-linux-gnu.tar.gz | tar -xz --directory=./mdbook
+        curl -Lf https://github.com/rust-lang/mdBook/releases/download/v0.4.13/mdbook-v0.4.13-x86_64-unknown-linux-gnu.tar.gz | tar -xz --directory=./mdbook
         echo `pwd`/mdbook >> $GITHUB_PATH
     - name: Generate Book
       run: |
diff --git a/book.toml b/book.toml
index 5470c3ba..2fb28d6d 100644
--- a/book.toml
+++ b/book.toml
@@ -4,3 +4,6 @@ title = "The Rust RFC Book"
 [output.html]
 no-section-label = true
 git-repository-url = "https://github.com/rust-lang/rfcs"
+
+[output.html.search]
+heading-split-level = 0