diff --git a/pkgs/applications/version-management/mercurial/default.nix b/pkgs/applications/version-management/mercurial/default.nix
index 128b70c38e85..3780be96fd6f 100644
--- a/pkgs/applications/version-management/mercurial/default.nix
+++ b/pkgs/applications/version-management/mercurial/default.nix
@@ -13,26 +13,13 @@ let
 
   self = python3Packages.buildPythonApplication rec {
     pname = "mercurial";
-    version = "5.8";
+    version = "5.9.1";
 
     src = fetchurl {
       url = "https://mercurial-scm.org/release/mercurial-${version}.tar.gz";
-      sha256 = "17rhlmmkqz5ll3k68jfzpcifg3nndbcbc2nx7kw8xn3qcj7nlpgw";
+      sha256 = "09wzyhyajy1dbp5kxkmvs9x8jk964wri19p5jgf83mv27i1zkvrj";
     };
 
-    patches = [
-      # https://phab.mercurial-scm.org/D10638, needed for below patch to apply
-      (fetchpatch {
-        url = "https://www.mercurial-scm.org/repo/hg/raw-rev/c365850b611490a5fdb235eb1cea310a542c2f84";
-        sha256 = "1gn3xvahbjdhbglffqpmj559w1bkqqsk70wqcanwv7nh972aqy9g";
-      })
-      # https://phab.mercurial-scm.org/D10639, fixes https://bz.mercurial-scm.org/show_bug.cgi?id=6514
-      (fetchpatch {
-        url = "https://www.mercurial-scm.org/repo/hg/raw-rev/c8f62920f07a40af3403ba9aefa1dac8a97d53ea";
-        sha256 = "1kw0xjg2c4jby0ncarjvpa5qafsyl1wzbk6jxls4hnxlxdl53nmn";
-      })
-    ];
-
     format = "other";
 
     passthru = { inherit python; }; # pass it so that the same version can be used in hg2git
@@ -40,7 +27,7 @@ let
     cargoDeps = if rustSupport then rustPlatform.fetchCargoTarball {
       inherit src;
       name = "${pname}-${version}";
-      sha256 = "1kc2giqvfwsdl5fb0qmz96ws1gdrs3skfdzvpiif2i8f7r4nqlhd";
+      sha256 = "1f7q0kmp46rphw38rlzh1yvpn3rdjdnzzbxzjkrjks8n1gm8baca";
       sourceRoot = "${pname}-${version}/rust";
     } else null;
     cargoRoot = if rustSupport then "rust" else null;