diff --git a/pkgs/by-name/ms/msgpack-cxx/package.nix b/pkgs/by-name/ms/msgpack-cxx/package.nix
index 73664813612d4..2a10fd5de1505 100644
--- a/pkgs/by-name/ms/msgpack-cxx/package.nix
+++ b/pkgs/by-name/ms/msgpack-cxx/package.nix
@@ -1,9 +1,10 @@
-{ lib
-, stdenv
-, fetchFromGitHub
-, cmake
-, boost
-, zlib
+{
+  lib,
+  stdenv,
+  fetchFromGitHub,
+  cmake,
+  boost,
+  zlib,
 }:
 
 stdenv.mkDerivation (finalAttrs: {
@@ -29,6 +30,7 @@ stdenv.mkDerivation (finalAttrs: {
 
   cmakeFlags = [
     "-DMSGPACK_BUILD_DOCS=OFF" # docs are not installed even if built
+    "-DMSGPACK_CXX20=ON"
   ] ++ lib.optional finalAttrs.finalPackage.doCheck "-DMSGPACK_BUILD_TESTS=ON";
 
   checkInputs = [