diff --git a/pkgs/servers/mail/spf-engine/default.nix b/pkgs/servers/mail/spf-engine/default.nix
index c90522edf041..326d42d5d78c 100644
--- a/pkgs/servers/mail/spf-engine/default.nix
+++ b/pkgs/servers/mail/spf-engine/default.nix
@@ -1,15 +1,17 @@
-{ lib, buildPythonApplication, fetchurl, pyspf, dnspython, authres, pymilter }:
+{ lib, buildPythonApplication, fetchurl, flit-core, pyspf, dnspython, authres, pymilter }:
 
 buildPythonApplication rec {
   pname = "spf-engine";
   version = "3.0.4";
-  format = "flit";
+  format = "pyproject";
 
   src = fetchurl {
     url = "https://launchpad.net/${pname}/${lib.versions.majorMinor version}/${version}/+download/${pname}-${version}.tar.gz";
     sha256 = "sha256-Gcw7enNIb/TrZEYa0Z04ezHUmfMmc1J+aEH6FlXbhTo=";
   };
 
+  nativeBuildInputs = [ flit-core ];
+
   propagatedBuildInputs = [ pyspf dnspython authres pymilter ];
 
   pythonImportsCheck = [