diff --git a/pkgs/by-name/ht/htmldoc/package.nix b/pkgs/by-name/ht/htmldoc/package.nix
index a2652191a926..a61a653af5e8 100644
--- a/pkgs/by-name/ht/htmldoc/package.nix
+++ b/pkgs/by-name/ht/htmldoc/package.nix
@@ -13,12 +13,12 @@
 
 stdenv.mkDerivation rec {
   pname = "htmldoc";
-  version = "1.9.20";
+  version = "1.9.21";
   src = fetchFromGitHub {
     owner = "michaelrsweet";
     repo = "htmldoc";
     rev = "v${version}";
-    hash = "sha256-nEDvG2Q6uMYWyb49EKOZimkOfEavCjvfFgucwi3u64k=";
+    hash = "sha256-MZKXEwJdQzn49JIUm4clqKBTtjKu6tBU5Sdq6ESn1k4=";
   };
 
   nativeBuildInputs = [ pkg-config ];