diff --git a/flake.lock b/flake.lock
index 7b466f5..7dc3852 100644
--- a/flake.lock
+++ b/flake.lock
@@ -32,22 +32,6 @@
         "type": "github"
       }
     },
-    "HTTP_3": {
-      "flake": false,
-      "locked": {
-        "lastModified": 1451647621,
-        "narHash": "sha256-oHIyw3x0iKBexEo49YeUDV1k74ZtyYKGR2gNJXXRxts=",
-        "owner": "phadej",
-        "repo": "HTTP",
-        "rev": "9bc0996d412fef1787449d841277ef663ad9a915",
-        "type": "github"
-      },
-      "original": {
-        "owner": "phadej",
-        "repo": "HTTP",
-        "type": "github"
-      }
-    },
     "Shrinker": {
       "flake": false,
       "locked": {
@@ -132,23 +116,6 @@
         "type": "github"
       }
     },
-    "cabal-32_3": {
-      "flake": false,
-      "locked": {
-        "lastModified": 1603716527,
-        "narHash": "sha256-sDbrmur9Zfp4mPKohCD8IDZfXJ0Tjxpmr2R+kg5PpSY=",
-        "owner": "haskell",
-        "repo": "cabal",
-        "rev": "94aaa8e4720081f9c75497e2735b90f6a819b08e",
-        "type": "github"
-      },
-      "original": {
-        "owner": "haskell",
-        "ref": "3.2",
-        "repo": "cabal",
-        "type": "github"
-      }
-    },
     "cabal-34": {
       "flake": false,
       "locked": {
@@ -183,23 +150,6 @@
         "type": "github"
       }
     },
-    "cabal-34_3": {
-      "flake": false,
-      "locked": {
-        "lastModified": 1622475795,
-        "narHash": "sha256-chwTL304Cav+7p38d9mcb+egABWmxo2Aq+xgVBgEb/U=",
-        "owner": "haskell",
-        "repo": "cabal",
-        "rev": "b086c1995cdd616fc8d91f46a21e905cc50a1049",
-        "type": "github"
-      },
-      "original": {
-        "owner": "haskell",
-        "ref": "3.4",
-        "repo": "cabal",
-        "type": "github"
-      }
-    },
     "cabal-36": {
       "flake": false,
       "locked": {
@@ -433,22 +383,6 @@
         "type": "github"
       }
     },
-    "cardano-shell_3": {
-      "flake": false,
-      "locked": {
-        "lastModified": 1608537748,
-        "narHash": "sha256-PulY1GfiMgKVnBci3ex4ptk2UNYMXqGjJOxcPy2KYT4=",
-        "owner": "input-output-hk",
-        "repo": "cardano-shell",
-        "rev": "9392c75087cb9a3d453998f4230930dea3a95725",
-        "type": "github"
-      },
-      "original": {
-        "owner": "input-output-hk",
-        "repo": "cardano-shell",
-        "type": "github"
-      }
-    },
     "cardano-wallet": {
       "flake": false,
       "locked": {
@@ -577,21 +511,6 @@
         "type": "github"
       }
     },
-    "flake-utils_3": {
-      "locked": {
-        "lastModified": 1623875721,
-        "narHash": "sha256-A8BU7bjS5GirpAUv4QA+QnJ4CceLHkcXdRp4xITDB0s=",
-        "owner": "numtide",
-        "repo": "flake-utils",
-        "rev": "f7e004a55b120c02ecb6219596820fcd32ca8772",
-        "type": "github"
-      },
-      "original": {
-        "owner": "numtide",
-        "repo": "flake-utils",
-        "type": "github"
-      }
-    },
     "flat": {
       "flake": false,
       "locked": {
@@ -677,23 +596,6 @@
         "type": "github"
       }
     },
-    "ghc-8.6.5-iohk_3": {
-      "flake": false,
-      "locked": {
-        "lastModified": 1600920045,
-        "narHash": "sha256-DO6kxJz248djebZLpSzTGD6s8WRpNI9BTwUeOf5RwY8=",
-        "owner": "input-output-hk",
-        "repo": "ghc",
-        "rev": "95713a6ecce4551240da7c96b6176f980af75cae",
-        "type": "github"
-      },
-      "original": {
-        "owner": "input-output-hk",
-        "ref": "release/8.6.5-iohk",
-        "repo": "ghc",
-        "type": "github"
-      }
-    },
     "gitignore-nix": {
       "flake": false,
       "locked": {
@@ -792,22 +694,6 @@
       }
     },
     "hackage_2": {
-      "flake": false,
-      "locked": {
-        "lastModified": 1638407533,
-        "narHash": "sha256-ja9xIX8eMQz1zFaqHuoeGztxVnUPqIpebfFPXQCtCmU=",
-        "owner": "input-output-hk",
-        "repo": "hackage.nix",
-        "rev": "5786405063958e417fdbcf7e75686f35d63708ac",
-        "type": "github"
-      },
-      "original": {
-        "owner": "input-output-hk",
-        "repo": "hackage.nix",
-        "type": "github"
-      }
-    },
-    "hackage_3": {
       "flake": false,
       "locked": {
         "lastModified": 1642554756,
@@ -912,27 +798,27 @@
     },
     "haskell-nix_2": {
       "inputs": {
-        "HTTP": "HTTP_3",
-        "cabal-32": "cabal-32_3",
-        "cabal-34": "cabal-34_3",
+        "HTTP": "HTTP_2",
+        "cabal-32": "cabal-32_2",
+        "cabal-34": "cabal-34_2",
         "cabal-36": "cabal-36",
-        "cardano-shell": "cardano-shell_3",
-        "flake-utils": "flake-utils_3",
-        "ghc-8.6.5-iohk": "ghc-8.6.5-iohk_3",
-        "hackage": "hackage_3",
-        "hpc-coveralls": "hpc-coveralls_3",
-        "nix-tools": "nix-tools_3",
+        "cardano-shell": "cardano-shell_2",
+        "flake-utils": "flake-utils_2",
+        "ghc-8.6.5-iohk": "ghc-8.6.5-iohk_2",
+        "hackage": "hackage_2",
+        "hpc-coveralls": "hpc-coveralls_2",
+        "nix-tools": "nix-tools_2",
         "nixpkgs": [
           "plutarch",
           "haskell-nix",
           "nixpkgs-2111"
         ],
-        "nixpkgs-2003": "nixpkgs-2003_3",
-        "nixpkgs-2105": "nixpkgs-2105_3",
+        "nixpkgs-2003": "nixpkgs-2003_2",
+        "nixpkgs-2105": "nixpkgs-2105_2",
         "nixpkgs-2111": "nixpkgs-2111_2",
-        "nixpkgs-unstable": "nixpkgs-unstable_3",
-        "old-ghc-nix": "old-ghc-nix_3",
-        "stackage": "stackage_3"
+        "nixpkgs-unstable": "nixpkgs-unstable_2",
+        "old-ghc-nix": "old-ghc-nix_2",
+        "stackage": "stackage_2"
       },
       "locked": {
         "lastModified": 1642811877,
@@ -1057,22 +943,6 @@
         "type": "github"
       }
     },
-    "hpc-coveralls_3": {
-      "flake": false,
-      "locked": {
-        "lastModified": 1607498076,
-        "narHash": "sha256-8uqsEtivphgZWYeUo5RDUhp6bO9j2vaaProQxHBltQk=",
-        "owner": "sevanspowell",
-        "repo": "hpc-coveralls",
-        "rev": "14df0f7d229f4cd2e79f8eabb1a740097fdfa430",
-        "type": "github"
-      },
-      "original": {
-        "owner": "sevanspowell",
-        "repo": "hpc-coveralls",
-        "type": "github"
-      }
-    },
     "hs-memory": {
       "flake": false,
       "locked": {
@@ -1189,22 +1059,6 @@
         "type": "github"
       }
     },
-    "nix-tools_3": {
-      "flake": false,
-      "locked": {
-        "lastModified": 1636018067,
-        "narHash": "sha256-ng306fkuwr6V/malWtt3979iAC4yMVDDH2ViwYB6sQE=",
-        "owner": "input-output-hk",
-        "repo": "nix-tools",
-        "rev": "ed5bd7215292deba55d6ab7a4e8c21f8b1564dda",
-        "type": "github"
-      },
-      "original": {
-        "owner": "input-output-hk",
-        "repo": "nix-tools",
-        "type": "github"
-      }
-    },
     "nixos-20_09": {
       "locked": {
         "lastModified": 1623585158,
@@ -1283,22 +1137,6 @@
         "type": "github"
       }
     },
-    "nixpkgs-2003_3": {
-      "locked": {
-        "lastModified": 1620055814,
-        "narHash": "sha256-8LEHoYSJiL901bTMVatq+rf8y7QtWuZhwwpKE2fyaRY=",
-        "owner": "NixOS",
-        "repo": "nixpkgs",
-        "rev": "1db42b7fe3878f3f5f7a4f2dc210772fd080e205",
-        "type": "github"
-      },
-      "original": {
-        "owner": "NixOS",
-        "ref": "nixpkgs-20.03-darwin",
-        "repo": "nixpkgs",
-        "type": "github"
-      }
-    },
     "nixpkgs-2009": {
       "locked": {
         "lastModified": 1624271064,
@@ -1315,22 +1153,6 @@
         "type": "github"
       }
     },
-    "nixpkgs-2009_2": {
-      "locked": {
-        "lastModified": 1624271064,
-        "narHash": "sha256-qns/uRW7MR2EfVf6VEeLgCsCp7pIOjDeR44JzTF09MA=",
-        "owner": "NixOS",
-        "repo": "nixpkgs",
-        "rev": "46d1c3f28ca991601a53e9a14fdd53fcd3dd8416",
-        "type": "github"
-      },
-      "original": {
-        "owner": "NixOS",
-        "ref": "nixpkgs-20.09-darwin",
-        "repo": "nixpkgs",
-        "type": "github"
-      }
-    },
     "nixpkgs-2105": {
       "locked": {
         "lastModified": 1630481079,
@@ -1348,22 +1170,6 @@
       }
     },
     "nixpkgs-2105_2": {
-      "locked": {
-        "lastModified": 1630481079,
-        "narHash": "sha256-leWXLchbAbqOlLT6tju631G40SzQWPqaAXQG3zH1Imw=",
-        "owner": "NixOS",
-        "repo": "nixpkgs",
-        "rev": "110a2c9ebbf5d4a94486854f18a37a938cfacbbb",
-        "type": "github"
-      },
-      "original": {
-        "owner": "NixOS",
-        "ref": "nixpkgs-21.05-darwin",
-        "repo": "nixpkgs",
-        "type": "github"
-      }
-    },
-    "nixpkgs-2105_3": {
       "locked": {
         "lastModified": 1640283157,
         "narHash": "sha256-6Ddfop+rKE+Gl9Tjp9YIrkfoYPzb8F80ergdjcq3/MY=",
@@ -1380,39 +1186,18 @@
       }
     },
     "nixpkgs-2111": {
-      "inputs": {
-        "HTTP": "HTTP_2",
-        "cabal-32": "cabal-32_2",
-        "cabal-34": "cabal-34_2",
-        "cardano-shell": "cardano-shell_2",
-        "flake-utils": "flake-utils_2",
-        "ghc-8.6.5-iohk": "ghc-8.6.5-iohk_2",
-        "hackage": "hackage_2",
-        "hpc-coveralls": "hpc-coveralls_2",
-        "nix-tools": "nix-tools_2",
-        "nixpkgs": [
-          "nixpkgs-2111",
-          "nixpkgs-2105"
-        ],
-        "nixpkgs-2003": "nixpkgs-2003_2",
-        "nixpkgs-2009": "nixpkgs-2009_2",
-        "nixpkgs-2105": "nixpkgs-2105_2",
-        "nixpkgs-unstable": "nixpkgs-unstable_2",
-        "old-ghc-nix": "old-ghc-nix_2",
-        "stackage": "stackage_2"
-      },
       "locked": {
-        "lastModified": 1641511340,
-        "narHash": "sha256-cdw4HbqukogROTYG4i9LarwN6+xtRRikO0g35tvAtYk=",
-        "owner": "input-output-hk",
-        "repo": "haskell.nix",
-        "rev": "4aeeba8d713d0b98c92c8c717df24da17d463c1d",
+        "lastModified": 1644510859,
+        "narHash": "sha256-xjpVvL5ecbyi0vxtVl/Fh9bwGlMbw3S06zE5nUzFB8A=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "0d1d5d7e3679fec9d07f2eb804d9f9fdb98378d3",
         "type": "github"
       },
       "original": {
-        "owner": "input-output-hk",
-        "repo": "haskell.nix",
-        "rev": "4aeeba8d713d0b98c92c8c717df24da17d463c1d",
+        "owner": "NixOS",
+        "ref": "nixpkgs-21.11-darwin",
+        "repo": "nixpkgs",
         "type": "github"
       }
     },
@@ -1465,22 +1250,6 @@
       }
     },
     "nixpkgs-unstable_2": {
-      "locked": {
-        "lastModified": 1635295995,
-        "narHash": "sha256-sGYiXjFlxTTMNb4NSkgvX+knOOTipE6gqwPUQpxNF+c=",
-        "owner": "NixOS",
-        "repo": "nixpkgs",
-        "rev": "22a500a3f87bbce73bd8d777ef920b43a636f018",
-        "type": "github"
-      },
-      "original": {
-        "owner": "NixOS",
-        "ref": "nixpkgs-unstable",
-        "repo": "nixpkgs",
-        "type": "github"
-      }
-    },
-    "nixpkgs-unstable_3": {
       "locked": {
         "lastModified": 1641285291,
         "narHash": "sha256-KYaOBNGar3XWTxTsYPr9P6u74KAqNq0wobEC236U+0c=",
@@ -1580,23 +1349,6 @@
         "type": "github"
       }
     },
-    "old-ghc-nix_3": {
-      "flake": false,
-      "locked": {
-        "lastModified": 1631092763,
-        "narHash": "sha256-sIKgO+z7tj4lw3u6oBZxqIhDrzSkvpHtv0Kki+lh9Fg=",
-        "owner": "angerman",
-        "repo": "old-ghc-nix",
-        "rev": "af48a7a7353e418119b6dfe3cd1463a657f342b8",
-        "type": "github"
-      },
-      "original": {
-        "owner": "angerman",
-        "ref": "master",
-        "repo": "old-ghc-nix",
-        "type": "github"
-      }
-    },
     "optparse-applicative": {
       "flake": false,
       "locked": {
@@ -1988,22 +1740,6 @@
       }
     },
     "stackage_2": {
-      "flake": false,
-      "locked": {
-        "lastModified": 1638062215,
-        "narHash": "sha256-1kOXkElNdsUOQ0RKVHWpfxh8Tl4I0rwwusESEDkrasI=",
-        "owner": "input-output-hk",
-        "repo": "stackage.nix",
-        "rev": "17d51e4b25d266beee4f5038258269b5f87a1551",
-        "type": "github"
-      },
-      "original": {
-        "owner": "input-output-hk",
-        "repo": "stackage.nix",
-        "type": "github"
-      }
-    },
-    "stackage_3": {
       "flake": false,
       "locked": {
         "lastModified": 1642468901,
diff --git a/flake.nix b/flake.nix
index 8e6fb0b..e4751d7 100644
--- a/flake.nix
+++ b/flake.nix
@@ -7,8 +7,7 @@
   inputs.haskell-nix.inputs.nixpkgs.follows = "haskell-nix/nixpkgs-unstable";
 
   # Temp workaround for Nix issue.
-  inputs.nixpkgs-2111.url =
-    "github:input-output-hk/haskell.nix?rev=4aeeba8d713d0b98c92c8c717df24da17d463c1d";
+  inputs.nixpkgs-2111.url = "github:NixOS/nixpkgs/nixpkgs-21.11-darwin";
 
   inputs.plutus.url =
     "github:input-output-hk/plutus?rev=65bad0fd53e432974c3c203b1b1999161b6c2dce";