diff --git a/pkgs/by-name/en/engage/mdbook-0.5-support.patch b/pkgs/by-name/en/engage/mdbook-0.5-support.patch
new file mode 100644
index 000000000000..0082bf5e7a37
--- /dev/null
+++ b/pkgs/by-name/en/engage/mdbook-0.5-support.patch
@@ -0,0 +1,16 @@
+--- a/book.toml
++++ b/book.toml
+@@ -1,6 +1,5 @@
+ [book]
+ language = "en"
+-multilingual = false
+ src = "book"
+ title = "Engage"
+
+@@ -8,5 +7,5 @@ build-dir = "public"
+
+ [output.html]
+-git-repository-icon = "fa-git-square"
++git-repository-icon = "fab-square-git"
+ git-repository-url = "https://gitlab.computer.surgery/charles/engage"
+
diff --git a/pkgs/by-name/en/engage/package.nix b/pkgs/by-name/en/engage/package.nix
index 6ae2bde48e24..2d57f8307c77 100644
--- a/pkgs/by-name/en/engage/package.nix
+++ b/pkgs/by-name/en/engage/package.nix
@@ -28,6 +28,11 @@ rustPlatform.buildRustPackage (finalAttrs: {
     hash = "sha256-n7ypFJBYT712Uzh1NnWWSOIpEDKR0e6sQxbiIN6pZgo=";
   };
 
+  patches = [
+    # Support mdbook 0.5.x - remove deprecated multilingual field
+    ./mdbook-0.5-support.patch
+  ];
+
   cargoHash = "sha256-UTIxxPBtxzsZilxriAT8ksl2ovoDzIhB+8f+b2cGN3k=";
 
   nativeBuildInputs = [