diff --git a/pkgs/development/libraries/science/math/or-tools/default.nix b/pkgs/development/libraries/science/math/or-tools/default.nix
index 741c6f4898b6..ca3e4a243691 100644
--- a/pkgs/development/libraries/science/math/or-tools/default.nix
+++ b/pkgs/development/libraries/science/math/or-tools/default.nix
@@ -16,14 +16,14 @@
 
 stdenv.mkDerivation rec {
   pname = "or-tools";
-  version = "9.0";
+  version = "9.1";
   disabled = python.pythonOlder "3.6";  # not supported upstream
 
   src = fetchFromGitHub {
     owner = "google";
     repo = "or-tools";
     rev = "v${version}";
-    sha256 = "0yihrsg8wj4b82xwg1hbn97my8zqd7xhw7dk7wm2axsyvqd6m3b3";
+    sha256 = "sha256-dEYMPWpa3J9EqtCq3kubdUYJivNRTOKUpNDx3UC1IcQ=";
   };
 
   # The original build system uses cmake which does things like pull