diff --git a/bucket/mdbook.json b/bucket/mdbook.json
index 259e92817f..9f16786874 100644
--- a/bucket/mdbook.json
+++ b/bucket/mdbook.json
@@ -1,12 +1,12 @@
 {
-    "version": "0.4.8",
+    "version": "0.4.9",
     "description": "Create a book from markdown files.",
     "homepage": "https://github.com/rust-lang/mdBook",
     "license": "MPL-2.0",
     "architecture": {
         "64bit": {
-            "url": "https://github.com/rust-lang/mdBook/releases/download/v0.4.8/mdbook-v0.4.8-x86_64-pc-windows-msvc.zip",
-            "hash": "beebc51a5705e0247471f57df814c8e9268a00a73c4cbd7fef5c834a9db4be0e"
+            "url": "https://github.com/rust-lang/mdBook/releases/download/v0.4.9/mdbook-v0.4.9-x86_64-pc-windows-msvc.zip",
+            "hash": "60d4b7db9d89d38ce803f57ebb09c380697b43cdc5417c395c9b0500332618c6"
         }
     },
     "bin": "mdbook.exe",