diff --git a/pkgs/development/python-modules/foolscap/default.nix b/pkgs/development/python-modules/foolscap/default.nix
index d1374ca71bf5..0c5a0fff79d2 100644
--- a/pkgs/development/python-modules/foolscap/default.nix
+++ b/pkgs/development/python-modules/foolscap/default.nix
@@ -9,11 +9,11 @@
 
 buildPythonPackage rec {
   pname = "foolscap";
-  version = "0.13.2";
+  version = "20.4.0";
 
   src = fetchPypi {
     inherit pname version;
-    sha256 = "8498c7e9eaecb5b19be74b18d55c2086440be08de29f2bb507f9b505757467ff";
+    sha256 = "0rbw9makjmawkcxnkkngybj3n14s0dnzn9gkqqq2krcm514kmlb9";
   };
 
   propagatedBuildInputs = [ mock twisted pyopenssl service-identity ];