diff --git a/default.nix b/default.nix
index 7b66620..88685a6 100644
--- a/default.nix
+++ b/default.nix
@@ -1,6 +1,11 @@
-{ pkgs ? import ./nix {}
+let flake = import ./nix/compat.nix;
+in
+{ pkgs ? import flake.inputs.nixpkgs { }
 , haskellPackages ? pkgs.haskellPackages
 }:
+let
+  pkgsWithArion = pkgs.extend flake.overlays.default;
+in
 {
-  arion = import ./nix/arion.nix { inherit pkgs haskellPackages; };
+  inherit (pkgsWithArion) arion;
 }
diff --git a/docs/flake-module.nix b/docs/flake-module.nix
new file mode 100644
index 0000000..a442d5d
--- /dev/null
+++ b/docs/flake-module.nix
@@ -0,0 +1,20 @@
+{
+  perSystem = { config, pkgs, ... }:
+    let
+      doc-options = import ./options.nix { };
+
+    in
+    {
+      packages.doc-options = pkgs.callPackage ./options.nix { };
+
+      checks.doc-options = pkgs.runCommand "doc-options-check" { } ''
+        if diff --color -u ${./modules/ROOT/partials/NixOSOptions.adoc} ${config.packages.doc-options}; then
+          touch $out
+        else
+          echo 1>&2 "The doc options have changed and need to be added."
+          echo 1>&2 "Please run ./update-options in the root of your arion clone."
+          exit 1
+        fi
+      '';
+    };
+}
diff --git a/flake.lock b/flake.lock
index 4e92b89..79b7879 100644
--- a/flake.lock
+++ b/flake.lock
@@ -1,21 +1,61 @@
 {
   "nodes": {
-    "nixpkgs": {
+    "flake-parts": {
+      "inputs": {
+        "nixpkgs-lib": [
+          "nixpkgs"
+        ]
+      },
       "locked": {
-        "lastModified": 1601906239,
-        "narHash": "sha256-P1jBYbYeFswig/0FKbgh+BpVhh9iurD3m0T2ae4gdx8=",
-        "owner": "NixOS",
-        "repo": "nixpkgs",
-        "rev": "c2bb4af48d26ed091e5674394bacbf8d488c7939",
+        "lastModified": 1669931201,
+        "narHash": "sha256-UnYFeaLPLj7e4eEt4GJooeJZhaZXyloQZYinwO/CeUw=",
+        "owner": "hercules-ci",
+        "repo": "flake-parts",
+        "rev": "995d6bc162c0539998ef6375c2c6b612972dc016",
         "type": "github"
       },
       "original": {
-        "id": "nixpkgs",
-        "type": "indirect"
+        "owner": "hercules-ci",
+        "ref": "easyOverlay",
+        "repo": "flake-parts",
+        "type": "github"
+      }
+    },
+    "haskell-flake": {
+      "locked": {
+        "lastModified": 1668167720,
+        "narHash": "sha256-5wDTR6xt9BB3BjgKR+YOjOkZgMyDXKaX79g42sStzDU=",
+        "owner": "srid",
+        "repo": "haskell-flake",
+        "rev": "4fc511d93a55fedf815c1647ad146c26d7a2054e",
+        "type": "github"
+      },
+      "original": {
+        "owner": "srid",
+        "repo": "haskell-flake",
+        "type": "github"
+      }
+    },
+    "nixpkgs": {
+      "locked": {
+        "lastModified": 1649668654,
+        "narHash": "sha256-XLLs2mjsnl4Yl9rBpfEwgvm+Tzd+RIta0N7lYdsbxHY=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "14aa201b658f43546b00153bb2ada7206ba8dd26",
+        "type": "github"
+      },
+      "original": {
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "14aa201b658f43546b00153bb2ada7206ba8dd26",
+        "type": "github"
       }
     },
     "root": {
       "inputs": {
+        "flake-parts": "flake-parts",
+        "haskell-flake": "haskell-flake",
         "nixpkgs": "nixpkgs"
       }
     }
diff --git a/flake.nix b/flake.nix
index b7fb810..ea674e4 100644
--- a/flake.nix
+++ b/flake.nix
@@ -1,44 +1,91 @@
 {
   description = "Arion - use Docker Compose via Nix";
 
-  outputs = { self, nixpkgs }:
-  let
-    lib = import (nixpkgs + "/lib");
-    systems = [
-      "aarch64-linux"
-      "x86_64-darwin"
-      "x86_64-linux"
-    ];
-    arionFromPkgs = pkgs: import ./nix/arion.nix { inherit pkgs; };
-  in {
-
-    # The overlay is currently the recommended way to integrate arion,
-    # because its arion attribute behaves just like Nixpkgs.
-    overlay = final: prev: {
-      arion = arionFromPkgs final;
-    };
-
-    packages = lib.genAttrs systems (system:
-    let
-      pkgs = nixpkgs.legacyPackages.${system};
-    in
-    {
-      arion = arionFromPkgs pkgs;
-    });
-
-    # Does not include the eval and build functions like you may expect from Nixpkgs.
-    defaultPackage = lib.genAttrs systems (system:
-      self.packages.${system}.arion
-    );
-
-    lib = {
-      eval = import ./src/nix/eval-composition.nix;
-      build = args@{...}:
-        let composition = self.lib.eval args;
-        in composition.config.out.dockerComposeYaml;
-    };
-
-    nixosModules.arion = ./nixos-module.nix;
-
+  inputs = {
+    nixpkgs.url = "github:NixOS/nixpkgs/14aa201b658f43546b00153bb2ada7206ba8dd26"; # TODO nixos-unstable
+    haskell-flake.url = "github:srid/haskell-flake";
+    flake-parts.url = "github:hercules-ci/flake-parts/easyOverlay"; # TODO merge
+    flake-parts.inputs.nixpkgs-lib.follows = "nixpkgs";
   };
+
+  outputs = inputs@{ self, flake-parts, ... }:
+    flake-parts.lib.mkFlake { inherit self; } ({ config, lib, extendModules, ... }: {
+      imports = [
+        inputs.haskell-flake.flakeModule
+        inputs.flake-parts.flakeModules.easyOverlay
+        ./docs/flake-module.nix
+        ./tests/flake-module.nix
+      ];
+      # FIXME use: systems = inputs.nixpkgs.lib.systems.flakeExposed;
+      systems = [ "x86_64-linux" "aarch64-linux" "x86_64-darwin" "aarch64-darwin" ];
+      perSystem = { config, self', inputs', pkgs, system, final, ... }:
+        let h = pkgs.haskell.lib.compose; in
+        {
+          overlayAttrs = {
+            inherit (config.packages) arion;
+            arionTestingFlags = {
+              dockerSupportsSystemd = false;
+            };
+          };
+          packages.default = config.packages.arion;
+          packages.overlay-test = final.arion;
+          packages.arion = import ./nix/arion.nix { inherit pkgs; };
+          haskellProjects.haskell-package = {
+            # not autodetected: https://github.com/srid/haskell-flake/issues/49
+            packages.arion-compose.root = ./.;
+
+            overrides =
+              self: super: {
+                arion-compose =
+                  lib.pipe super.arion-compose [
+                    (h.addBuildTools [ pkgs.nix ])
+                    (h.overrideCabal (o: {
+                      src = pkgs.lib.sourceByRegex ./. [
+                        ".*[.]cabal"
+                        "LICENSE"
+                        "src/?.*"
+                        "README.asciidoc"
+                        "CHANGELOG.md"
+                      ];
+                      preCheck = ''
+                        export NIX_LOG_DIR=$TMPDIR
+                        export NIX_STATE_DIR=$TMPDIR
+                        export NIX_PATH=nixpkgs=${pkgs.path}
+                      '';
+                    }))
+                  ];
+              };
+          };
+          devShells.default = config.devShells.haskell-package.overrideAttrs (o: {
+            nativeBuildInputs = o.nativeBuildInputs or [ ] ++ [
+              pkgs.docker-compose
+              pkgs.nixpkgs-fmt
+              config.haskellProjects.haskell-package.haskellPackages.releaser
+            ];
+          });
+        };
+      flake = {
+        debug = { inherit inputs config lib; };
+
+        defaultPackage =
+          lib.mapAttrs
+            (ps: lib.warn "arion.defaultPackage has been removed in favor of arion.packages.\${system}.default"
+              ps.default)
+            config.flake.packages;
+
+        lib = {
+          eval = import ./src/nix/eval-composition.nix;
+          build = args@{ ... }:
+            let composition = self.lib.eval args;
+            in composition.config.out.dockerComposeYaml;
+        };
+        nixosModules.arion = ./nixos-module.nix;
+        herculesCI.ciSystems = [
+          # "aarch64-darwin"
+          # "aarch64-linux"
+          "x86_64-darwin"
+          "x86_64-linux"
+        ];
+      };
+    });
 }
diff --git a/nix/ci.nix b/nix/ci.nix
deleted file mode 100644
index 1e53108..0000000
--- a/nix/ci.nix
+++ /dev/null
@@ -1,46 +0,0 @@
-let
-  sources = import ./sources.nix;
-  lib = import (sources."nixos-unstable" + "/lib");
-  inherit (import (sources."project.nix" + "/lib/dimension.nix") { inherit lib; }) dimension;
-in
-
-dimension "Nixpkgs version" {
-    "nixos-22_05" = {
-      nixpkgsSource = "nixos-22.05";
-      enableDoc = true;
-    };
-    "nixos-unstable" = {
-      nixpkgsSource = "nixos-unstable";
-      isReferenceNixpkgs = true; # match ./default.nix
-      enableDoc = true;
-    };
-  } (
-    _name: { nixpkgsSource, isReferenceNixpkgs ? false, enableDoc ? true,
-             dockerSupportsSystemd ? false, nixosHasPodmanDockerSocket ? true }:
-
-
-      dimension "System" {
-        "x86_64-linux" = { isReferenceTarget = isReferenceNixpkgs; };
-        "x86_64-darwin" = { enableNixOSTests = false; };
-      } (
-        system: { isReferenceTarget ? false, enableNixOSTests ? true }:
-          let
-            pkgs = import ./. {
-              inherit system dockerSupportsSystemd nixosHasPodmanDockerSocket;
-              nixpkgsSrc = sources.${nixpkgsSource};
-            };
-          in
-          {
-            inherit (pkgs) arion;
-          } // lib.optionalAttrs enableNixOSTests {
-            inherit (pkgs) tests;
-          } // lib.optionalAttrs enableDoc {
-            inherit (pkgs) 
-              # FIXME: nixpkgs antora packaging is broken
-              # doc
-              doc-options doc-options-check;
-          } // lib.optionalAttrs isReferenceTarget {
-            inherit (pkgs.arion-project.haskellPkgs) arion-compose-checked;
-          }
-      )
-  )
diff --git a/nix/compat.nix b/nix/compat.nix
new file mode 100644
index 0000000..f867cea
--- /dev/null
+++ b/nix/compat.nix
@@ -0,0 +1,10 @@
+(import
+  (
+    let lock = builtins.fromJSON (builtins.readFile ./flake.lock); in
+    fetchTarball {
+      url = "https://github.com/edolstra/flake-compat/archive/009399224d5e398d03b22badca40a37ac85412a1.tar.gz";
+      sha256 = "sha256:0xcr9fibnapa12ywzcnlf54wrmbqqb96fmmv8043zhsycws7bpqy";
+    }
+  )
+  { src = ../.; }
+).defaultNix
diff --git a/nix/default.nix b/nix/default.nix
deleted file mode 100644
index 5cc58ac..0000000
--- a/nix/default.nix
+++ /dev/null
@@ -1,23 +0,0 @@
-{ sources ? import ./sources.nix
-, nixpkgsName ? "nixos-unstable" # match ./ci.nix isReferenceNixpkgs
-, nixpkgsSrc ? sources.${nixpkgsName}
-, system ? builtins.currentSystem
-, dockerSupportsSystemd ? false
-, nixosHasPodmanDockerSocket ? true
-, ...
-}:
-
-import nixpkgsSrc ({
-  # Makes the config pure as well. See <nixpkgs>/top-level/impure.nix:
-  config = {
-  };
-  overlays = [
-    (_: _: {
-      arionTestingFlags = {
-        inherit dockerSupportsSystemd nixosHasPodmanDockerSocket;
-      };
-    })
-    (import ./overlay.nix)
-  ];
-  inherit system;
-})
diff --git a/nix/haskell-overlay.nix b/nix/haskell-overlay.nix
deleted file mode 100644
index f0c5ccb..0000000
--- a/nix/haskell-overlay.nix
+++ /dev/null
@@ -1,16 +0,0 @@
-self: super: hself: hsuper:
-{
-  arion-compose = import ./haskell-arion-compose.nix { pkgs = self; haskellPackages = hself; };
-  arion-compose-checked =
-              let pkg = /* super.haskell.lib.buildStrictly  currently broken in nixos-unstable */ hself.arion-compose;
-                  checked = super.haskell.lib.overrideCabal pkg (o: {
-                    postConfigure = ''${o.postConfigure or ""}
-                      if ! ${hsuper.cabal-install}/bin/cabal check;
-                      then
-                        echo 1>&2 ERROR: cabal file is invalid. Above warnings were errors.
-                        exit 1
-                      fi
-                    '';
-                  });
-              in checked;
-}
\ No newline at end of file
diff --git a/nix/overlay.nix b/nix/overlay.nix
deleted file mode 100644
index ecdb6af..0000000
--- a/nix/overlay.nix
+++ /dev/null
@@ -1,60 +0,0 @@
-self: super:
-let
-  inherit (self.arion-project) haskellPkgs;
-  inherit (super) lib;
-
-  sources = import ./sources.nix;
-
-  fakeRepo = src: super.runCommand "source" { inherit src; nativeBuildInputs = [super.git]; } ''
-    cp -r --no-preserve=mode $src $out
-    git init
-    cp -r .git $out
-  '';
-
-in
-{
-
-  inherit (import ./.. { pkgs = self; }) arion;
-  tests = super.callPackage ../tests {};
-
-  doc-options = import ../docs/options.nix {};
-  doc-options-check = self.runCommand "doc-options-check" {} ''
-    if diff --color -u ${../docs/modules/ROOT/partials/NixOSOptions.adoc} ${self.doc-options}; then
-      touch $out
-    else
-      echo 1>&2 "The doc options have changed and need to be added."
-      echo 1>&2 "Please run ./update-options in the root of your arion clone."
-      exit 1
-    fi
-  '';
-  doc = self.stdenv.mkDerivation { 
-    name = "arion-documentation"; 
-    nativeBuildInputs = [super.antora];
-    src = fakeRepo ../.;
-    HOME = ".";
-    buildPhase = "antora antora-playbook";
-    installPhase = ''
-      mkdir $out
-      mv public/* $out/
-    '';
-  };
-
-  arion-project = super.recurseIntoAttrs {
-    haskellPkgs = super.haskellPackages.extend (import ./haskell-overlay.nix self super);
-    shell = haskellPkgs.shellFor {
-      packages = p: [p.arion-compose];
-      nativeBuildInputs = [
-        haskellPkgs.cabal-install
-        haskellPkgs.ghcid
-        haskellPkgs.haskell-language-server
-        super.docker-compose
-        self.niv
-        self.nixpkgs-fmt
-        self.releaser
-      ];
-    };
-  };
-
-  inherit (import (sources.niv) {}) niv;
-  releaser = self.haskellPackages.callCabal2nix "releaser" sources.releaser {};
-}
diff --git a/nix/sources.json b/nix/sources.json
deleted file mode 100644
index 037ef0c..0000000
--- a/nix/sources.json
+++ /dev/null
@@ -1,63 +0,0 @@
-{
-    "niv": {
-        "branch": "master",
-        "description": "Easy dependency management for Nix projects",
-        "homepage": "https://github.com/nmattia/niv",
-        "owner": "nmattia",
-        "repo": "niv",
-        "rev": "fad2a6cbfb2e7cdebb7cb0ad2f5cc91e2c9bc06b",
-        "sha256": "0mghc1j0rd15spdjx81bayjqr0khc062cs25y5dcfzlxk4ynyc6m",
-        "type": "tarball",
-        "url": "https://github.com/nmattia/niv/archive/fad2a6cbfb2e7cdebb7cb0ad2f5cc91e2c9bc06b.tar.gz",
-        "url_template": "https://github.com/<owner>/<repo>/archive/<rev>.tar.gz"
-    },
-    "nixos-22.05": {
-        "branch": "nixos-22.05",
-        "description": "Nix Packages collection",
-        "homepage": null,
-        "owner": "NixOS",
-        "repo": "nixpkgs",
-        "rev": "a634c8f6c1fbf9b9730e01764999666f3436f10a",
-        "sha256": "1d40v43x972li5fg7jadxkj341li41mf2cl6vv7xi6j80rkq45q4",
-        "type": "tarball",
-        "url": "https://github.com/NixOS/nixpkgs/archive/a634c8f6c1fbf9b9730e01764999666f3436f10a.tar.gz",
-        "url_template": "https://github.com/<owner>/<repo>/archive/<rev>.tar.gz"
-    },
-    "nixos-unstable": {
-        "branch": "lib-modules-allow-disable-_modules.args-docs-internal",
-        "description": "A read-only mirror of NixOS/nixpkgs tracking the released channels. Send issues and PRs to",
-        "homepage": "https://github.com/NixOS/nixpkgs",
-        "owner": "hercules-ci",
-        "repo": "nixpkgs",
-        "rev": "14aa201b658f43546b00153bb2ada7206ba8dd26",
-        "sha256": "0xn43gdn3rfys1d8ni3y6x7vxyc263qsbhfsjwc5x7pcd3dfrcjw",
-        "type": "tarball",
-        "url": "https://github.com/hercules-ci/nixpkgs/archive/14aa201b658f43546b00153bb2ada7206ba8dd26.tar.gz",
-        "url_template": "https://github.com/<owner>/<repo>/archive/<rev>.tar.gz",
-        "version": ""
-    },
-    "project.nix": {
-        "branch": "master",
-        "description": "A configuration manager for your projects",
-        "homepage": null,
-        "owner": "hercules-ci",
-        "repo": "project.nix",
-        "rev": "2e598501e7fda6993d2a1a281aa296b26d01e10c",
-        "sha256": "1rkzpzxpg69px6qwchdlg4xf5irv0snrzk2l6vrs9rsx48gqax9j",
-        "type": "tarball",
-        "url": "https://github.com/hercules-ci/project.nix/archive/2e598501e7fda6993d2a1a281aa296b26d01e10c.tar.gz",
-        "url_template": "https://github.com/<owner>/<repo>/archive/<rev>.tar.gz"
-    },
-    "releaser": {
-        "branch": "master",
-        "description": "Automation of Haskell package release process.",
-        "homepage": null,
-        "owner": "domenkozar",
-        "repo": "releaser",
-        "rev": "52a2bb0b2ce0bc15d4e7b11d8761a28d82c0c083",
-        "sha256": "178lv0a0qxd8six0rm83j7wjwlsad1hysdrk4mb38fagbb8csagb",
-        "type": "tarball",
-        "url": "https://github.com/domenkozar/releaser/archive/52a2bb0b2ce0bc15d4e7b11d8761a28d82c0c083.tar.gz",
-        "url_template": "https://github.com/<owner>/<repo>/archive/<rev>.tar.gz"
-    }
-}
diff --git a/nix/sources.nix b/nix/sources.nix
deleted file mode 100644
index b796fff..0000000
--- a/nix/sources.nix
+++ /dev/null
@@ -1,171 +0,0 @@
-# This file has been generated by Niv.
-
-let
-
-  #
-  # The fetchers. fetch_<type> fetches specs of type <type>.
-  #
-
-  fetch_file = pkgs: name: spec:
-    let
-      name' = sanitizeName name + "-src";
-    in
-      if spec.builtin or true then
-        builtins_fetchurl { inherit (spec) url sha256; name = name'; }
-      else
-        pkgs.fetchurl { inherit (spec) url sha256; name = name'; };
-
-  fetch_tarball = pkgs: name: spec:
-    let
-      name' = sanitizeName name + "-src";
-    in
-      if spec.builtin or true then
-        builtins_fetchTarball { name = name'; inherit (spec) url sha256; }
-      else
-        pkgs.fetchzip { name = name'; inherit (spec) url sha256; };
-
-  fetch_git = name: spec:
-    let
-      ref =
-        if spec ? ref then spec.ref else
-          if spec ? branch then "refs/heads/${spec.branch}" else
-            if spec ? tag then "refs/tags/${spec.tag}" else
-              abort "In git source '${name}': Please specify `ref`, `tag` or `branch`!";
-    in
-      builtins.fetchGit { url = spec.repo; inherit (spec) rev; inherit ref; };
-
-  fetch_local = spec: spec.path;
-
-  fetch_builtin-tarball = name: throw
-    ''[${name}] The niv type "builtin-tarball" is deprecated. You should instead use `builtin = true`.
-        $ niv modify ${name} -a type=tarball -a builtin=true'';
-
-  fetch_builtin-url = name: throw
-    ''[${name}] The niv type "builtin-url" will soon be deprecated. You should instead use `builtin = true`.
-        $ niv modify ${name} -a type=file -a builtin=true'';
-
-  #
-  # Various helpers
-  #
-
-  # https://github.com/NixOS/nixpkgs/pull/83241/files#diff-c6f540a4f3bfa4b0e8b6bafd4cd54e8bR695
-  sanitizeName = name:
-    (
-      concatMapStrings (s: if builtins.isList s then "-" else s)
-        (
-          builtins.split "[^[:alnum:]+._?=-]+"
-            ((x: builtins.elemAt (builtins.match "\\.*(.*)" x) 0) name)
-        )
-    );
-
-  # The set of packages used when specs are fetched using non-builtins.
-  mkPkgs = sources: system:
-    let
-      sourcesNixpkgs =
-        import (builtins_fetchTarball { inherit (sources.nixpkgs) url sha256; }) { inherit system; };
-      hasNixpkgsPath = builtins.any (x: x.prefix == "nixpkgs") builtins.nixPath;
-      hasThisAsNixpkgsPath = <nixpkgs> == ./.;
-    in
-      if builtins.hasAttr "nixpkgs" sources
-      then sourcesNixpkgs
-      else if hasNixpkgsPath && ! hasThisAsNixpkgsPath then
-        import <nixpkgs> {}
-      else
-        abort
-          ''
-            Please specify either <nixpkgs> (through -I or NIX_PATH=nixpkgs=...) or
-            add a package called "nixpkgs" to your sources.json.
-          '';
-
-  # The actual fetching function.
-  fetch = pkgs: name: spec:
-
-    if ! builtins.hasAttr "type" spec then
-      abort "ERROR: niv spec ${name} does not have a 'type' attribute"
-    else if spec.type == "file" then fetch_file pkgs name spec
-    else if spec.type == "tarball" then fetch_tarball pkgs name spec
-    else if spec.type == "git" then fetch_git name spec
-    else if spec.type == "local" then fetch_local spec
-    else if spec.type == "builtin-tarball" then fetch_builtin-tarball name
-    else if spec.type == "builtin-url" then fetch_builtin-url name
-    else
-      abort "ERROR: niv spec ${name} has unknown type ${builtins.toJSON spec.type}";
-
-  # If the environment variable NIV_OVERRIDE_${name} is set, then use
-  # the path directly as opposed to the fetched source.
-  replace = name: drv:
-    let
-      saneName = stringAsChars (c: if isNull (builtins.match "[a-zA-Z0-9]" c) then "_" else c) name;
-      ersatz = builtins.getEnv "NIV_OVERRIDE_${saneName}";
-    in
-      if ersatz == "" then drv else ersatz;
-
-  # Ports of functions for older nix versions
-
-  # a Nix version of mapAttrs if the built-in doesn't exist
-  mapAttrs = builtins.mapAttrs or (
-    f: set: with builtins;
-    listToAttrs (map (attr: { name = attr; value = f attr set.${attr}; }) (attrNames set))
-  );
-
-  # https://github.com/NixOS/nixpkgs/blob/0258808f5744ca980b9a1f24fe0b1e6f0fecee9c/lib/lists.nix#L295
-  range = first: last: if first > last then [] else builtins.genList (n: first + n) (last - first + 1);
-
-  # https://github.com/NixOS/nixpkgs/blob/0258808f5744ca980b9a1f24fe0b1e6f0fecee9c/lib/strings.nix#L257
-  stringToCharacters = s: map (p: builtins.substring p 1 s) (range 0 (builtins.stringLength s - 1));
-
-  # https://github.com/NixOS/nixpkgs/blob/0258808f5744ca980b9a1f24fe0b1e6f0fecee9c/lib/strings.nix#L269
-  stringAsChars = f: s: concatStrings (map f (stringToCharacters s));
-  concatMapStrings = f: list: concatStrings (map f list);
-  concatStrings = builtins.concatStringsSep "";
-
-  # https://github.com/NixOS/nixpkgs/blob/8a9f58a375c401b96da862d969f66429def1d118/lib/attrsets.nix#L331
-  optionalAttrs = cond: as: if cond then as else {};
-
-  # fetchTarball version that is compatible between all the versions of Nix
-  builtins_fetchTarball = { url, name ? null, sha256 }@attrs:
-    let
-      inherit (builtins) lessThan nixVersion fetchTarball;
-    in
-      if lessThan nixVersion "1.12" then
-        fetchTarball ({ inherit url; } // (optionalAttrs (!isNull name) { inherit name; }))
-      else
-        fetchTarball attrs;
-
-  # fetchurl version that is compatible between all the versions of Nix
-  builtins_fetchurl = { url, name ? null, sha256 }@attrs:
-    let
-      inherit (builtins) lessThan nixVersion fetchurl;
-    in
-      if lessThan nixVersion "1.12" then
-        fetchurl ({ inherit url; } // (optionalAttrs (!isNull name) { inherit name; }))
-      else
-        fetchurl attrs;
-
-  # Create the final "sources" from the config
-  mkSources = config:
-    mapAttrs (
-      name: spec:
-        if builtins.hasAttr "outPath" spec
-        then abort
-          "The values in sources.json should not have an 'outPath' attribute"
-        else
-          spec // { outPath = replace name (fetch config.pkgs name spec); }
-    ) config.sources;
-
-  # The "config" used by the fetchers
-  mkConfig =
-    { sourcesFile ? if builtins.pathExists ./sources.json then ./sources.json else null
-    , sources ? if isNull sourcesFile then {} else builtins.fromJSON (builtins.readFile sourcesFile)
-    , system ? builtins.currentSystem
-    , pkgs ? mkPkgs sources system
-    }: rec {
-      # The sources, i.e. the attribute set of spec name to spec
-      inherit sources;
-
-      # The "pkgs" (evaluated nixpkgs) to use for e.g. non-builtin fetchers
-      inherit pkgs;
-    };
-
-in
-mkSources (mkConfig {}) // { __functor = _: settings: mkSources (mkConfig settings); }
diff --git a/shell.nix b/shell.nix
index f6c0ea0..8745f50 100644
--- a/shell.nix
+++ b/shell.nix
@@ -1 +1 @@
-args@{...}: (import ./nix args).arion-project.shell
+(builtins.getFlake ("git+file://" + toString ./.)).devShells.${builtins.currentSystem}.default
diff --git a/tests/arion-test/default.nix b/tests/arion-test/default.nix
index 9c7a14a..6035d0d 100644
--- a/tests/arion-test/default.nix
+++ b/tests/arion-test/default.nix
@@ -1,4 +1,4 @@
-{ usePodman ? false, pkgs, lib, ... }:
+{ usePodman ? false, pkgs, lib ? pkgs.lib, ... }:
 
 let
   # To make some prebuilt derivations available in the vm
diff --git a/tests/default.nix b/tests/default.nix
deleted file mode 100644
index 70012ac..0000000
--- a/tests/default.nix
+++ /dev/null
@@ -1,46 +0,0 @@
-{ pkgs ? import ../pkgs.nix, arionTestingFlags ? {} }:
-let
-  inherit (pkgs) nixosTest recurseIntoAttrs arion lib;
-
-  hasEvalModulesType = (lib.evalModules { modules = [ {} ]; })?type;
-
-in
-
-recurseIntoAttrs {
-
-  test = nixosTest ./arion-test;
-
-  nixosModuleWithDocker =
-    lib.optionalAttrs
-      hasEvalModulesType
-      (
-        import ./nixos-virtualization-arion-test/test.nix pkgs {
-          virtualisation.arion.backend = "docker";
-        }
-      );
-
-  nixosModuleWithPodman =
-    lib.optionalAttrs
-      (hasEvalModulesType && arionTestingFlags.nixosHasPodmanDockerSocket)
-      (
-        import ./nixos-virtualization-arion-test/test.nix pkgs {
-          virtualisation.arion.backend = "podman-socket";
-        }
-      );
-
-  testWithPodman =
-    if arionTestingFlags.nixosHasPodmanDockerSocket
-    then nixosTest (import ./arion-test { usePodman = true; inherit pkgs lib; })
-    else {};
-
-  testBuild = arion.build {
-
-    # To be more accurately, you can do
-    #   pkgs = import ../examples/minimal/arion-pkgs.nix;
-    # but this is quite efficient:
-    inherit pkgs;
-
-    modules = [ ../examples/minimal/arion-compose.nix ];
-  };
-
-}
diff --git a/tests/flake-module.nix b/tests/flake-module.nix
new file mode 100644
index 0000000..bbfdb1d
--- /dev/null
+++ b/tests/flake-module.nix
@@ -0,0 +1,35 @@
+{
+  perSystem = { pkgs, final, ... }:
+    let
+      inherit (final) nixosTest arion lib;
+    in
+    {
+      checks = lib.optionalAttrs pkgs.stdenv.isLinux {
+        test = nixosTest ./arion-test;
+
+        nixosModuleWithDocker =
+          import ./nixos-virtualization-arion-test/test.nix final {
+            virtualisation.arion.backend = "docker";
+          };
+
+        nixosModuleWithPodman =
+          import ./nixos-virtualization-arion-test/test.nix final {
+            virtualisation.arion.backend = "podman-socket";
+          };
+
+        testWithPodman =
+          nixosTest (import ./arion-test { usePodman = true; pkgs = final; });
+
+        testBuild = arion.build {
+
+          # To be more accurate, we could do
+          #   pkgs = import ../examples/minimal/arion-pkgs.nix;
+          # But let's avoid re-evaluating Nixpkgs
+          pkgs = final;
+
+          modules = [ ../examples/minimal/arion-compose.nix ];
+        };
+
+      };
+    };
+}
diff --git a/update-options b/update-options
index 14a66e9..0e7a02c 100755
--- a/update-options
+++ b/update-options
@@ -1,9 +1,9 @@
 #!/usr/bin/env nix-shell
-#!nix-shell -i bash
+#!nix-shell -i bash -p jq
 
 set -eu -o pipefail
 
 cd "$(dirname ${BASH_SOURCE[0]})"
 
-doc_options="$(nix-build nix -A doc-options)"
+doc_options="$(nix build .#doc-options --json | jq -r .[].outputs.out)"
 cat "$doc_options" >docs/modules/ROOT/partials/NixOSOptions.adoc