diff --git a/pkgs/applications/networking/mailreaders/mmh/default.nix b/pkgs/applications/networking/mailreaders/mmh/default.nix
index fe74e922230d..50bbb0b0f664 100644
--- a/pkgs/applications/networking/mailreaders/mmh/default.nix
+++ b/pkgs/applications/networking/mailreaders/mmh/default.nix
@@ -1,13 +1,13 @@
-{ lib, stdenv, fetchurl, ncurses, autoreconfHook, flex }:
-let rev = "431604647f89d5aac7b199a7883e98e56e4ccf9e";
+{ lib, stdenv, fetchurl, fetchpatch, ncurses, autoreconfHook, flex }:
+let rev = "b17ea39dc17e5514f33b3f5c34ede92bd16e208c";
 in stdenv.mkDerivation rec {
   pname = "mmh";
-  version = "unstable-2019-09-08";
+  version = "unstable-2020-08-21";
 
   src = fetchurl {
     url = "http://git.marmaro.de/?p=mmh;a=snapshot;h=${rev};sf=tgz";
     name = "mmh-${rev}.tgz";
-    sha256 = "1q97p4g3f1q2m567i2dbx7mm7ixw3g91ww2rymwj42cxk9iyizhv";
+    sha256 = "1bqfxafw4l2y46pnsxgy4ji1xlyifzw01k1ykbsjj9p61q3nv6l6";
   };
 
   postPatch = ''