diff --git a/channels.nix b/channels.nix
deleted file mode 100644
index 55e0683..0000000
--- a/channels.nix
+++ /dev/null
@@ -1,37 +0,0 @@
-{ lib
-, fetchFromGitHub
-, fetchgit
-, overlays
-}:
-
-let
-
-  channelSpecToChannel = name: channel:
-    if (channel.tag == "fetch_from_github") then fetchFromGitHub ((removeAttrs channel ["tag" "name"]))
-    else if (channel.tag == "fetch_git") then fetchgit (removeAttrs channel ["tag" "name"])
-    else if (channel.tag == "path") then channel.path else null;
-
-in
-
-rec {
-  channels = {
-    nixpkgs = {
-      tag = "fetch_from_github";
-      owner = "NixOS";
-      repo = "nixpkgs";
-      rev = "973910f5c31b9ba6c171c33a8bd7199990b14c72";
-      sha256 = "1n1kibmn1fcjazaxp8lydwdx646lknqksv5b2fm33fdq2dvafvj7";
-    };
-
-    nixpkgs-unstable = {
-      tag = "fetch_from_github";
-      owner = "NixOS";
-      repo = "nixpkgs";
-      rev = "ecaf3da9340231e5493eccc3db87604a3705da42";
-      sha256 = "049dcpzklpjj0c7g172njfcqb9xvxkpyf7qjiwvaf8klgd5cippa";
-    };
-  };
-
-  importedOverlays = lib.mapAttrsToList (name: value: import (channelSpecToChannel name value)) overlays;
-  importedChannels = lib.mapAttrs (name: value: import (channelSpecToChannel name value) { overlays = importedOverlays; }) channels;
-}
diff --git a/codedown.nix b/codedown.nix
index 0aec05c..9d6a6a9 100644
--- a/codedown.nix
+++ b/codedown.nix
@@ -1,5 +1,4 @@
 { pkgsStable
-, pkgsUnstable
 , pkgsMaster
 , requiredPackages ? []
 , system ? "x86_64-linux"
@@ -15,7 +14,7 @@ let
 in
 
 rec {
-  spellchecker = pkgsUnstable.callPackage ./language_servers/markdown-spellcheck-lsp {};
+  spellchecker = pkgsMaster.callPackage ./language_servers/markdown-spellcheck-lsp {};
 
   testing = {
     builds-forever = pkgsMaster.callPackage ./misc/builds-forever.nix {};
@@ -58,11 +57,11 @@ rec {
   languages = everythingEnv.config.builtKernels;
 
   makeEnvironment = callPackage ./codedown/makeEnvironment.nix {
-    inherit pkgsStable pkgsUnstable pkgsMaster;
+    inherit pkgsStable pkgsMaster;
   };
 
   validateCodeDownEnvironment = callPackage ./codedown/validateCodeDownEnvironment.nix {};
 
   # Exposed so it's easier to compute build dependencies in the presence of IFD
-  inherit pkgsStable pkgsUnstable requiredPackages;
+  inherit pkgsStable pkgsMaster requiredPackages;
 }
diff --git a/codedown/makeEnvironment.nix b/codedown/makeEnvironment.nix
index a81665c..8cc2be8 100644
--- a/codedown/makeEnvironment.nix
+++ b/codedown/makeEnvironment.nix
@@ -8,7 +8,6 @@
 , writeText
 
 , pkgsStable
-, pkgsUnstable
 , pkgsMaster
 
 , name ? "codedown-environment"
diff --git a/default.nix b/default.nix
index 10f3bb3..4b80bf5 100644
--- a/default.nix
+++ b/default.nix
@@ -12,13 +12,6 @@ let
     hash = "sha256-D2YTs7K33zAzoQdAcVzePgDn6bdIEexGgHluoB07+Yw="; # nixpkgs-sha256
   }) { inherit overlays; };
 
-  pkgsUnstable = import (fetchFromGitHub {
-    owner = "NixOS";
-    repo = "nixpkgs";
-    rev = "ab82a9612aa45284d4adf69ee81871a389669a9e"; # nixpkgs-unstable-rev
-    hash = "sha256-5r0pInVo5d6Enti0YwUSQK4TebITypB42bWy5su3MrQ="; # nixpkgs-unstable-sha256
-  }) { inherit overlays; };
-
   pkgsMaster = import (fetchFromGitHub {
     owner = "NixOS";
     repo = "nixpkgs";
@@ -28,4 +21,4 @@ let
 
 in
 
-pkgsStable.callPackage ./codedown.nix { inherit pkgsStable pkgsUnstable pkgsMaster; }
+pkgsStable.callPackage ./codedown.nix { inherit pkgsStable pkgsMaster; }
diff --git a/flake.lock b/flake.lock
index 9d4906a..1e83b64 100644
--- a/flake.lock
+++ b/flake.lock
@@ -47,28 +47,11 @@
         "type": "github"
       }
     },
-    "nixpkgs-unstable": {
-      "locked": {
-        "lastModified": 1720368505,
-        "narHash": "sha256-5r0pInVo5d6Enti0YwUSQK4TebITypB42bWy5su3MrQ=",
-        "owner": "NixOS",
-        "repo": "nixpkgs",
-        "rev": "ab82a9612aa45284d4adf69ee81871a389669a9e",
-        "type": "github"
-      },
-      "original": {
-        "owner": "NixOS",
-        "ref": "nixpkgs-unstable",
-        "repo": "nixpkgs",
-        "type": "github"
-      }
-    },
     "root": {
       "inputs": {
         "flake-utils": "flake-utils",
         "nixpkgs": "nixpkgs",
-        "nixpkgs-master": "nixpkgs-master",
-        "nixpkgs-unstable": "nixpkgs-unstable"
+        "nixpkgs-master": "nixpkgs-master"
       }
     }
   },
diff --git a/flake.nix b/flake.nix
index 8a01bb9..0499acc 100644
--- a/flake.nix
+++ b/flake.nix
@@ -2,20 +2,18 @@
   description = "CodeDown languages";
 
   inputs.nixpkgs.url = "github:NixOS/nixpkgs/release-24.05";
-  inputs.nixpkgs-unstable.url = "github:NixOS/nixpkgs/nixpkgs-unstable";
   inputs.nixpkgs-master.url = "github:NixOS/nixpkgs/master";
 
   inputs.flake-utils.url = "github:numtide/flake-utils";
 
-  outputs = { self, nixpkgs, nixpkgs-unstable, nixpkgs-master, flake-utils }@inputs:
+  outputs = { self, nixpkgs, nixpkgs-master, flake-utils }@inputs:
     flake-utils.lib.eachDefaultSystem (system:
       let
         overlays = [(import ./overlays.nix)];
         pkgsStable = import nixpkgs { inherit system overlays; };
-        pkgsUnstable = import nixpkgs-unstable { inherit system overlays; };
         pkgsMaster = import nixpkgs-master { inherit system overlays; };
 
-        codedown = import ./codedown.nix { inherit pkgsStable pkgsUnstable pkgsMaster; };
+        codedown = import ./codedown.nix { inherit pkgsStable pkgsMaster; };
 
       in
         rec {
diff --git a/tests/flake.lock b/tests/flake.lock
index 4cfc1c1..364e470 100644
--- a/tests/flake.lock
+++ b/tests/flake.lock
@@ -31,27 +31,10 @@
         "type": "github"
       }
     },
-    "nixpkgsUnstable": {
-      "locked": {
-        "lastModified": 1721080040,
-        "narHash": "sha256-USDsS90/88RJibP3gEcH1AaVt+JpnX4XCUD9bAJP5I4=",
-        "owner": "NixOS",
-        "repo": "nixpkgs",
-        "rev": "b2c1f10bfbb3f617ea8e8669ac13f3f56ceb2ea2",
-        "type": "github"
-      },
-      "original": {
-        "owner": "NixOS",
-        "ref": "nixpkgs-unstable",
-        "repo": "nixpkgs",
-        "type": "github"
-      }
-    },
     "root": {
       "inputs": {
         "flake-utils": "flake-utils",
-        "nixpkgs": "nixpkgs",
-        "nixpkgsUnstable": "nixpkgsUnstable"
+        "nixpkgs": "nixpkgs"
       }
     }
   },
diff --git a/tests/flake.nix b/tests/flake.nix
index 7779795..0a3f270 100644
--- a/tests/flake.nix
+++ b/tests/flake.nix
@@ -1,15 +1,13 @@
 {
   inputs.nixpkgs.url = "github:NixOS/nixpkgs/release-24.05";
-  inputs.nixpkgsUnstable.url = "github:NixOS/nixpkgs/nixpkgs-unstable";
 
   inputs.flake-utils.url = "github:numtide/flake-utils";
 
-  outputs = { self, nixpkgs, nixpkgsUnstable, flake-utils }@inputs:
+  outputs = { self, nixpkgs, flake-utils }@inputs:
     # flake-utils.lib.eachDefaultSystem (system:
     flake-utils.lib.eachSystem ["x86_64-linux"] (system:
       let
         pkgs = import nixpkgs { inherit system; };
-        pkgsUnstable = import nixpkgsUnstable { inherit system; };
         tests = pkgs.haskell.packages.ghc965.callPackage ./tests.nix {};
       in
         rec {
@@ -18,7 +16,6 @@
             inherit (pkgs) cabal2nix;
 
             nixpkgsPath = pkgs.writeShellScriptBin "nixpkgsPath.sh" "echo -n ${pkgs.path}";
-            nixpkgsUnstablePath = pkgsUnstable.writeShellScriptBin "nixpkgsPath.sh" "echo -n ${pkgsUnstable.path}";
 
             # Print a trivial PATH that we can use to run kernel and LSP tests, to ensure
             # they aren't depending on anything on the test machine's PATH.