diff --git a/npins/default.nix b/npins/default.nix
index fb04b70..8d8f2bf 100644
--- a/npins/default.nix
+++ b/npins/default.nix
@@ -1,7 +1,7 @@
 # Generated by npins. Do not modify; will be overwritten regularly
 let
   data = builtins.fromJSON (builtins.readFile ./sources.json);
-  version = data.version;
+  inherit (data) version;
 
   mkSource =
     spec:
@@ -27,7 +27,6 @@ let
       revision,
       url ? null,
       hash,
-      branch ? null,
       ...
     }:
     assert repository ? type;
@@ -36,7 +35,7 @@ let
     if url != null then
       (builtins.fetchTarball {
         inherit url;
-        sha256 = hash;
+        sha256 = hash; # FIXME: check nix version & use SRI hashes
       })
     else
       assert repository.type == "Git";
@@ -54,10 +53,10 @@ let
         name = urlToName repository.url revision;
       in
       builtins.fetchGit {
-        url = repository.url;
+        inherit (repository) url;
         rev = revision;
         inherit name;
-        narHash = hash;
+        # hash = hash;
       };
 
   mkPyPiSource =
@@ -74,7 +73,7 @@ let
       sha256 = hash;
     };
 in
-if version == 4 then
+if version == 3 then
   builtins.mapAttrs (_: mkSource) data.pins
 else
   throw "Unsupported format version ${toString version} in sources.json. Try running `npins upgrade`"
diff --git a/npins/sources.json b/npins/sources.json
index fceb491..6ff3fa4 100644
--- a/npins/sources.json
+++ b/npins/sources.json
@@ -9,7 +9,7 @@
       "branch": "master",
       "revision": "608f8008ebd5e7a535544cbc8df18ea4a64bb66a",
       "url": null,
-      "hash": "sha256-yCA/QwWcwOs9dtVxHaHFCu2LNMOhhyUeZG1XpaZrNFE="
+      "hash": "0l9ldfkaamvdchg2b1x1qcs8pv8aqnhiswfmfqyyph4w0m1ky868"
     },
     "nixpkgs": {
       "type": "Channel",
@@ -18,5 +18,5 @@
       "hash": "08wwq26cd2g7h58bfavgvfmhwp2kh5v3qvf1a35xvd1rp20lzs3d"
     }
   },
-  "version": 4
-}
+  "version": 3
+}
\ No newline at end of file