diff --git a/pkgs/applications/science/logic/why3/default.nix b/pkgs/applications/science/logic/why3/default.nix
index 228d1a7c4d40..d1fb853ee9e1 100644
--- a/pkgs/applications/science/logic/why3/default.nix
+++ b/pkgs/applications/science/logic/why3/default.nix
@@ -2,15 +2,15 @@
 
 stdenv.mkDerivation rec {
   name    = "why3-${version}";
-  version = "0.85";
+  version = "0.86.1";
 
   src = fetchurl {
-    url    = "https://gforge.inria.fr/frs/download.php/34074/why3-0.85.tar.gz";
-    sha256 = "0sj1pd50lqvnvyss1f8ysgigdi64s91rrpdrmp7crmcy1npa8apf";
+    url    = https://gforge.inria.fr/frs/download.php/file/34797/why3-0.86.1.tar.gz;
+    sha256 = "129kzq79n8h480zrlphgh1ixvwp3wm18nbcky9bp4wdnr6zaibd7";
   };
 
   buildInputs = with ocamlPackages;
-    [ coq coq.camlp5 ocaml findlib lablgtk ocamlgraph zarith ];
+    [ coq coq.camlp5 ocaml findlib lablgtk ocamlgraph zarith menhir ];
 
   meta = with stdenv.lib; {
     description = "A platform for deductive program verification";