diff --git a/pkgs/applications/version-management/mercurial/default.nix b/pkgs/applications/version-management/mercurial/default.nix
index fc4c18f5eb7..7f72e24aa53 100644
--- a/pkgs/applications/version-management/mercurial/default.nix
+++ b/pkgs/applications/version-management/mercurial/default.nix
@@ -4,7 +4,7 @@
 
 let
   # if you bump version, update pkgs.tortoisehg too or ping maintainer
-  version = "4.9";
+  version = "4.9.1";
   name = "mercurial-${version}";
   inherit (python2Packages) docutils hg-git dulwich python;
 in python2Packages.buildPythonApplication {
@@ -13,7 +13,7 @@ in python2Packages.buildPythonApplication {
 
   src = fetchurl {
     url = "https://mercurial-scm.org/release/${name}.tar.gz";
-    sha256 = "01ig0464cvy9d87rn274g39frxr0p5q4lxf1xn5k3m24grf0qq0g";
+    sha256 = "0iybbkd9add066729zg01kwz5hhc1s6lhp9rrnsmzq6ihyxj3p8v";
   };
 
   inherit python; # pass it so that the same version can be used in hg2git