diff --git a/pkgs/development/lisp-modules/lisp-packages.nix b/pkgs/development/lisp-modules/lisp-packages.nix
index 3e51daf0ee8..ff95bb4a000 100644
--- a/pkgs/development/lisp-modules/lisp-packages.nix
+++ b/pkgs/development/lisp-modules/lisp-packages.nix
@@ -37,7 +37,7 @@ let lispPackages = rec {
     description = "Iteration package for Common Lisp";
     deps = [];
     src = (pkgs.lib.overrideDerivation (pkgs.fetchdarcs {
-      url = "http://common-lisp.net/project/iterate/darcs/iterate";
+      url = "https://common-lisp.net/project/iterate/darcs/iterate";
       sha256 = "0gm05s3laiivsqgqjfj1rkz83c2c0jyn4msfgbv6sz42znjpam25";
       context = ./iterate.darcs-context;
     }) (x: {SSL_CERT_FILE=pkgs.cacert + "/etc/ca-bundle.crt";}));