diff --git a/Dockerfile b/Dockerfile
index 3ac9242..7892264 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -6,7 +6,7 @@ WORKDIR /build
 COPY . .
 
 RUN apk add wget gzip tar && \
-    wget -O mdbook.tar.gz https://github.com/rust-lang/mdBook/releases/download/v0.4.37/mdbook-v0.4.37-x86_64-unknown-linux-musl.tar.gz && \
+    wget -O mdbook.tar.gz https://github.com/rust-lang/mdBook/releases/download/v0.4.40/mdbook-v0.4.40-x86_64-unknown-linux-musl.tar.gz && \
     tar xvf mdbook.tar.gz && \
     ./mdbook build