diff --git a/pkgs/python-packages.nix b/pkgs/python-packages.nix
--- a/pkgs/python-packages.nix
+++ b/pkgs/python-packages.nix
@@ -315,13 +315,13 @@
     };
   };
   mercurial = super.buildPythonPackage {
-    name = "mercurial-4.0.2";
+    name = "mercurial-4.1";
     buildInputs = with self; [];
     doCheck = false;
     propagatedBuildInputs = with self; [];
     src = fetchurl {
-      url = "https://pypi.python.org/packages/85/1b/0296aacd697228974a473d2508f013532f987ed6b1bacfe5abd6d5be6332/mercurial-4.0.2.tar.gz";
-      md5 = "fa72a08e2723e4fa2a21c4e66437f3fa";
+      url = "https://pypi.python.org/packages/d4/fb/2068126deba02802ba556da217b891b3480056b51f83591c9178b3d64d80/mercurial-4.1.tar.gz";
+      md5 = "59c7072a70c8b41dbde801f935c47aea";
     };
     meta = {
       license = [ pkgs.lib.licenses.gpl1 pkgs.lib.licenses.gpl2Plus ];
diff --git a/requirements.txt b/requirements.txt
--- a/requirements.txt
+++ b/requirements.txt
@@ -6,7 +6,7 @@ configobj==5.0.6
 dulwich==0.13.0
 hgsubversion==1.8.6
 infrae.cache==1.0.1
-mercurial==4.0.2
+mercurial==4.1.0
 msgpack-python==0.4.8
 pyramid-jinja2==2.5
 pyramid==1.7.4
@@ -28,7 +28,6 @@ zope.interface==4.1.3
 ## debug
 ipdb==0.10.1
 ipython==5.1.0
-
 # http servers
 gevent==1.1.2
 greenlet==0.4.10