diff --git a/bucket/mdbook.json b/bucket/mdbook.json
index e8629b9c62..2b987e7e40 100644
--- a/bucket/mdbook.json
+++ b/bucket/mdbook.json
@@ -1,12 +1,12 @@
 {
-    "version": "0.4.1",
+    "version": "0.4.2",
     "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/v0.4.1/mdbook-v0.4.1-x86_64-pc-windows-msvc.zip",
-            "hash": "020112f87404cf08abff760d72ba0bca1a2cab98ea4b0e7b4fe08ce7a2f2778e"
+            "url": "https://github.com/rust-lang/mdBook/releases/download/v0.4.2/mdbook-v0.4.2-x86_64-pc-windows-msvc.zip",
+            "hash": "6c225ef79988bc6f171dd3c9ac6a86195b8e8bb0597cfaba6d48c479918f20b4"
         }
     },
     "bin": "mdbook.exe",