diff --git a/pkgs/development/tools/parsing/byacc/default.nix b/pkgs/development/tools/parsing/byacc/default.nix
index f71b28d7e127..1b1b31deaedb 100644
--- a/pkgs/development/tools/parsing/byacc/default.nix
+++ b/pkgs/development/tools/parsing/byacc/default.nix
@@ -2,14 +2,14 @@
 
 stdenv.mkDerivation rec {
   pname = "byacc";
-  version = "20210619";
+  version = "20210802";
 
   src = fetchurl {
     urls = [
       "ftp://ftp.invisible-island.net/byacc/${pname}-${version}.tgz"
       "https://invisible-mirror.net/archives/byacc/${pname}-${version}.tgz"
     ];
-    sha256 = "sha256-rN1ggNz5NXMqCOyOjEwWHGZs1W2MSQc5xtu2JnpJjA4=";
+    sha256 = "sha256-KUnGftE71nkX8Mm8yFx22ZowkNIRBep2cqh6NQLjzPY=";
   };
 
   configureFlags = [