diff --git a/.github/workflows/doctest/action.yml b/.github/workflows/doctest/action.yml
new file mode 100644
index 0000000..7e686b5
--- /dev/null
+++ b/.github/workflows/doctest/action.yml
@@ -0,0 +1,48 @@
+name: "Run doctest on a Cabal package"
+
+inputs:
+  ghc:
+    description: 'Which GHC version to use for doctest'
+    type: string
+    required: true
+  version:
+    description: 'Which version of doctest to use'
+    type: string
+    required: false
+    default: 'latest'
+
+outputs:
+  path:
+    description: "The path to the doctest executable"
+    value: ${{ steps.result.outputs.result }}
+
+runs:
+  using: "composite"
+  steps:
+    - name: "Check for cached executable"
+      id: cache
+      uses: actions/github-script@v7
+      with:
+        result-encoding: string
+        script: |
+          const tc = require('@actions/tool-cache');
+          return null;
+
+    - name: "Setup Haskell environment"
+      id: setup
+      uses: haskell-actions/setup@v2.7
+      with:
+        ghc-version: "${{ inputs.ghc }}"
+        cabal-update: true
+
+    - name: "Result"
+      id: result
+      uses: actions/github-script@v7
+      with:
+        result-encoding: string
+        script: |
+          if (${{ steps.cache.outputs.result }}) {
+            return ${{ steps.cache.outputs.result }};
+          } else {
+            return null;
+          }
diff --git a/.github/workflows/linters.yml b/.github/workflows/linters.yml
new file mode 100644
index 0000000..1fd86ed
--- /dev/null
+++ b/.github/workflows/linters.yml
@@ -0,0 +1,51 @@
+name: Run linters
+
+on:
+  pull_request: {}
+  push:
+    branches:
+      - "main"
+
+jobs:
+  cabal-gild:
+    runs-on: ubuntu-latest
+    steps:
+      - name: 'Set up cabal-gild'
+        uses: tfausak/cabal-gild-setup-action@v2
+
+      - name: 'Checkout the repository'
+        uses: actions/checkout@v4
+
+      - name: 'Check package'
+        run: cabal-gild --mode check --input os-string-aeson.cabal
+
+  fourmolu:
+    runs-on: ubuntu-latest
+    steps:
+      - name: 'Checkout the repository'
+        uses: actions/checkout@v4
+
+      - name: 'Check that the source code is formatted'
+        uses: fourmolu/fourmolu-action@v10
+        with:
+          pattern: |
+            src/**/*.hs
+            os-string-aeson-internal/**/*.hs
+            examples/**/*.hs
+            test/**/*.hs
+
+  hlint:
+    runs-on: ubuntu-latest
+    steps:
+      - name: 'Checkout the repository'
+        uses: actions/checkout@v4
+
+      - name: 'Set up HLint'
+        uses: haskell-actions/hlint-setup@v2
+
+      - name: 'Run HLint'
+        uses: haskell-actions/hlint-run@v2
+        with:
+          path: '["src", "os-string-aeson-internal", "examples", "test"]'
+          fail-on: warning
+
diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index 92b5483..d111dce 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -39,6 +39,39 @@ jobs:
           ghc-version: "${{ matrix.ghc }}"
           cabal-update: true
 
+      - name: "Install doctest"
+        id: install-doctest
+        shell: bash
+        run: |
+          if [[ "${RUNNER_TEMP}" == '' ]]; then
+            echo 'Expected $RUNNER_TEMP to be defined'
+            exit 1
+          fi
+
+          if [[ "${RUNNER_TOOL_CACHE}" == '' ]]; then
+            echo 'Expected $RUNNER_TOOL_CACHE to be defined'
+            exit 1
+          fi
+
+          doctest="doctest-${{ steps.setup.outputs.ghc-version }}"
+          if [[ "${{ runner.os }}" == 'Windows' ]]; then
+            doctest="${doctest}.exe"
+          fi
+          result="${RUNNER_TOOL_CACHE}/${doctest}"
+
+          if [[ ! -x "${result}" ]]; then
+            tmpdir="$(mktemp -d "${RUNNER_TEMP}/doctest.XXXX")"
+            cabal install --ignore-project --installdir "${tmpdir}" --install-method copy doctest
+            installed="${tmpdir}/doctest"
+            if [[ "${{ runner.os }}" == 'Windows' ]]; then
+              installed="${installed}.exe"
+            fi
+            cp "${installed}" "${result}"
+          fi
+          "${result}" --version
+
+          echo "path=${result}" >> "${GITHUB_OUTPUT}"
+
       - name: "Configure the build"
         run: |
           cabal configure --enable-tests --enable-benchmarks --disable-documentation
@@ -58,7 +91,9 @@ jobs:
       - name: "Install dependencies"
         # If we had an exact cache hit, the dependencies will be up to date.
         if: steps.cache.outputs.cache-hit != 'true'
-        run: cabal build all --only-dependencies --enable-documentation
+        run: |
+          cabal build all --only-dependencies
+          cabal build all --only-dependencies --enable-documentation
 
       - name: "Save cached dependencies"
         # Cache dependencies already here, so that we do not have to rebuild them should the subsequent steps fail.
@@ -78,16 +113,13 @@ jobs:
       - name: "Run doctests"
         shell: bash
         run: |
-          if [[ "${{ runner.os }}" == 'Windows' ]]
-          then
-            doctest="$HOME/.local/bin/doctest.exe"
-          else
-            doctest="$HOME/.local/bin/doctest"
-          fi
-          cabal install --ignore-project --installdir "$HOME/.local/bin" doctest
-          "${doctest}" --version
-          cabal repl --with-compiler "${doctest}" 'os-string-aeson:lib:os-string-aeson-internal'
-          cabal repl --with-compiler "${doctest}" 'os-string-aeson:lib:os-string-aeson'
+          targets=(
+            'os-string-aeson:lib:os-string-aeson-internal'
+            'os-string-aeson:lib:os-string-aeson'
+          )
+          for target in "${targets[@]}"; do
+            cabal repl --with-compiler "${{ steps.install-doctest.outputs.path }}" --build-depends aeson "${target}"
+          done
 
       - name: "Check cabal file"
         run: cabal check
diff --git a/.mergify.yml b/.mergify.yml
index e92aba5..1238dd8 100644
--- a/.mergify.yml
+++ b/.mergify.yml
@@ -4,6 +4,8 @@ queue_rules:
       # See https://docs.mergify.io/conditions/#validating-all-status-checks
       - 'check-success~=.* on ubuntu-latest'
       - 'check-success~=.* on windows-latest'
+    merge_method: squash
+
 pull_request_rules:
   - name: 'Automatically merge pull requests'
     conditions:
@@ -13,9 +15,9 @@ pull_request_rules:
     actions:
       queue:
         name: default
-        method: squash
+
   - name: 'Delete head branch after merge'
     conditions:
-      - merged
+      - 'merged'
     actions:
       delete_head_branch: {}
diff --git a/os-string-aeson.cabal b/os-string-aeson.cabal
index 069137a..b116a3a 100644
--- a/os-string-aeson.cabal
+++ b/os-string-aeson.cabal
@@ -30,7 +30,7 @@ extra-doc-files:
 tested-with:
   ghc ==8.10.7 || ==9.0.2 || ==9.2.8 || ==9.4.8 || ==9.6.6 || ==9.8.2 || ==9.10.1
 
-flag old-os-string
+flag os-string
   description: Use an older version of the os-string library.
   manual: False
   default: False
@@ -51,6 +51,20 @@ common language
 
   default-language: Haskell2010
 
+common os-string-compat
+  if flag(os-string)
+    -- We don't actually need filepath, but we want to make sure that it is not
+    -- <1.5 if it brought into scope by some tool (Looking at you, doctest).
+    build-depends:
+      filepath >=1.5,
+      os-string >=2.0.0 && <2.1,
+  else
+    build-depends:
+      filepath >=1.4.100.0 && <1.6,
+      os-string <2,
+
+    ghc-options: -Wno-deprecations
+
 common rts
   ghc-options:
     -threaded
@@ -59,34 +73,21 @@ common rts
 
 library
   import: language
+  import: os-string-compat
   hs-source-dirs: src/
   build-depends:
     base,
     os-string-aeson-internal,
 
-  -- Dependencies for doctests
-  build-depends:
-    aeson
-
   -- cabal-gild: discover ./src/ --exclude=Setup.hs --exclude=**/Include.hs
   exposed-modules:
     System.OsString.Aeson
     System.OsString.Aeson.Posix
     System.OsString.Aeson.Windows
 
-  -- Only needed for doctests
-  if flag(old-os-string)
-    build-depends:
-      filepath >=1.4.100.0 && <1.5,
-      os-string <2,
-
-    ghc-options: -Wno-deprecations
-  else
-    build-depends:
-      os-string >=2.0.0 && <2.1
-
 library os-string-aeson-internal
   import: language
+  import: os-string-compat
   visibility: public
   hs-source-dirs: os-string-aeson-internal/
   build-depends:
@@ -105,18 +106,9 @@ library os-string-aeson-internal
     System.OsString.Aeson.Internal.Types
     System.OsString.Aeson.Internal.Windows
 
-  if flag(old-os-string)
-    build-depends:
-      filepath >=1.4.100.0 && <1.5,
-      os-string <2,
-
-    ghc-options: -Wno-deprecations
-  else
-    build-depends:
-      os-string >=2.0.0 && <2.1
-
 test-suite examples
   import: language
+  import: os-string-compat
   import: rts
   type: exitcode-stdio-1.0
   hs-source-dirs: examples
@@ -135,18 +127,9 @@ test-suite examples
     HKD2
     Utils
 
-  if flag(old-os-string)
-    build-depends:
-      filepath >=1.4.100.0 && <1.5,
-      os-string <2,
-
-    ghc-options: -Wno-deprecations
-  else
-    build-depends:
-      os-string >=2.0.0 && <2.1
-
 test-suite test
   import: language
+  import: os-string-compat
   import: rts
   type: exitcode-stdio-1.0
   hs-source-dirs: test
@@ -170,16 +153,6 @@ test-suite test
     Units.Posix
     Units.Windows
 
-  if flag(old-os-string)
-    build-depends:
-      filepath >=1.4.100.0 && <1.5,
-      os-string <2,
-
-    ghc-options: -Wno-deprecations
-  else
-    build-depends:
-      os-string >=2.0.0 && <2.1
-
 source-repository head
   type: git
   location: https://github.com/mmhat/os-string-aeson
diff --git a/stack.ghc-9.2.yaml b/stack.ghc-9.2.yaml
deleted file mode 100644
index 0bb8b24..0000000
--- a/stack.ghc-9.2.yaml
+++ /dev/null
@@ -1,10 +0,0 @@
-resolver: lts-20.26
-
-extra-deps:
-  - base64-1.0@sha256:ab8084608505f30d6cf7dd790271f927fd8a00956c5e7f5546f5cf56b298022c,2991
-  - os-string-2.0.6@sha256:7699e7ae9bf74d056a62f384ceef8dfb2aa660f3f7c8016e9703f3b995e5e030,3259
-  - text-2.0.2@sha256:71b5fa8c64d3c1fd0a08f993463220867b08290a2256e94b0952bf0e8f5a45cc,9905
-
-flags:
-  os-string-aeson:
-    old-os-string: false
diff --git a/stack.ghc-9.2.yaml.lock b/stack.ghc-9.2.yaml.lock
deleted file mode 100644
index 0943081..0000000
--- a/stack.ghc-9.2.yaml.lock
+++ /dev/null
@@ -1,33 +0,0 @@
-# This file was autogenerated by Stack.
-# You should not edit this file by hand.
-# For more information, please see the documentation at:
-#   https://docs.haskellstack.org/en/stable/lock_files
-
-packages:
-- completed:
-    hackage: base64-1.0@sha256:ab8084608505f30d6cf7dd790271f927fd8a00956c5e7f5546f5cf56b298022c,2991
-    pantry-tree:
-      sha256: 62150ae24db8e07f966679024406de4cdfe13556c9afce807f4f24d7ec03d0b5
-      size: 2229
-  original:
-    hackage: base64-1.0@sha256:ab8084608505f30d6cf7dd790271f927fd8a00956c5e7f5546f5cf56b298022c,2991
-- completed:
-    hackage: os-string-2.0.6@sha256:7699e7ae9bf74d056a62f384ceef8dfb2aa660f3f7c8016e9703f3b995e5e030,3259
-    pantry-tree:
-      sha256: 4743363ed98362a8541108a2e7febb7ba32acd337d29dbff4472fafbe246589c
-      size: 2218
-  original:
-    hackage: os-string-2.0.6@sha256:7699e7ae9bf74d056a62f384ceef8dfb2aa660f3f7c8016e9703f3b995e5e030,3259
-- completed:
-    hackage: text-2.0.2@sha256:71b5fa8c64d3c1fd0a08f993463220867b08290a2256e94b0952bf0e8f5a45cc,9905
-    pantry-tree:
-      sha256: 25f3b6dd211e30f9e0ef5047bb9f30df7a9296cf1043873e31558196dfe78676
-      size: 7514
-  original:
-    hackage: text-2.0.2@sha256:71b5fa8c64d3c1fd0a08f993463220867b08290a2256e94b0952bf0e8f5a45cc,9905
-snapshots:
-- completed:
-    sha256: 5a59b2a405b3aba3c00188453be172b85893cab8ebc352b1ef58b0eae5d248a2
-    size: 650475
-    url: https://raw.githubusercontent.com/commercialhaskell/stackage-snapshots/master/lts/20/26.yaml
-  original: lts-20.26
diff --git a/stack.ghc-9.4.yaml b/stack.ghc-9.4.yaml
deleted file mode 100644
index c159253..0000000
--- a/stack.ghc-9.4.yaml
+++ /dev/null
@@ -1,8 +0,0 @@
-resolver: lts-21.25
-
-extra-deps:
-  - base64-1.0@sha256:ab8084608505f30d6cf7dd790271f927fd8a00956c5e7f5546f5cf56b298022c,2991
-
-flags:
-  os-string-aeson:
-    old-os-string: false
diff --git a/stack.ghc-9.4.yaml.lock b/stack.ghc-9.4.yaml.lock
deleted file mode 100644
index 707d2a6..0000000
--- a/stack.ghc-9.4.yaml.lock
+++ /dev/null
@@ -1,19 +0,0 @@
-# This file was autogenerated by Stack.
-# You should not edit this file by hand.
-# For more information, please see the documentation at:
-#   https://docs.haskellstack.org/en/stable/lock_files
-
-packages:
-- completed:
-    hackage: base64-1.0@sha256:ab8084608505f30d6cf7dd790271f927fd8a00956c5e7f5546f5cf56b298022c,2991
-    pantry-tree:
-      sha256: 62150ae24db8e07f966679024406de4cdfe13556c9afce807f4f24d7ec03d0b5
-      size: 2229
-  original:
-    hackage: base64-1.0@sha256:ab8084608505f30d6cf7dd790271f927fd8a00956c5e7f5546f5cf56b298022c,2991
-snapshots:
-- completed:
-    sha256: a81fb3877c4f9031e1325eb3935122e608d80715dc16b586eb11ddbff8671ecd
-    size: 640086
-    url: https://raw.githubusercontent.com/commercialhaskell/stackage-snapshots/master/lts/21/25.yaml
-  original: lts-21.25
diff --git a/stack.ghc-9.6.yaml b/stack.ghc-9.6.yaml
deleted file mode 100644
index 5ca4c58..0000000
--- a/stack.ghc-9.6.yaml
+++ /dev/null
@@ -1,8 +0,0 @@
-resolver: lts-22.31
-
-extra-deps:
-  - base64-1.0@sha256:ab8084608505f30d6cf7dd790271f927fd8a00956c5e7f5546f5cf56b298022c,2991
-
-flags:
-  os-string-aeson:
-    old-os-string: false
diff --git a/stack.ghc-9.6.yaml.lock b/stack.ghc-9.6.yaml.lock
deleted file mode 100644
index 25e2bdc..0000000
--- a/stack.ghc-9.6.yaml.lock
+++ /dev/null
@@ -1,19 +0,0 @@
-# This file was autogenerated by Stack.
-# You should not edit this file by hand.
-# For more information, please see the documentation at:
-#   https://docs.haskellstack.org/en/stable/lock_files
-
-packages:
-- completed:
-    hackage: base64-1.0@sha256:ab8084608505f30d6cf7dd790271f927fd8a00956c5e7f5546f5cf56b298022c,2991
-    pantry-tree:
-      sha256: 62150ae24db8e07f966679024406de4cdfe13556c9afce807f4f24d7ec03d0b5
-      size: 2229
-  original:
-    hackage: base64-1.0@sha256:ab8084608505f30d6cf7dd790271f927fd8a00956c5e7f5546f5cf56b298022c,2991
-snapshots:
-- completed:
-    sha256: acaab6ca693211938d1542abcb1c83a2f298b9f6b571854a9d38febe39b6408e
-    size: 719577
-    url: https://raw.githubusercontent.com/commercialhaskell/stackage-snapshots/master/lts/22/31.yaml
-  original: lts-22.31
diff --git a/stack.yaml b/stack.yaml
index 84c8558..4572b94 120000
--- a/stack.yaml
+++ b/stack.yaml
@@ -1 +1 @@
-stack.ghc-9.6.yaml
\ No newline at end of file
+stack/stack.ghc-9.6.yaml
\ No newline at end of file
diff --git a/stack.yaml.lock b/stack.yaml.lock
index 06be9ba..b3d91aa 120000
--- a/stack.yaml.lock
+++ b/stack.yaml.lock
@@ -1 +1 @@
-stack.ghc-9.6.yaml.lock
\ No newline at end of file
+stack/stack.ghc-9.6.yaml.lock
\ No newline at end of file
diff --git a/stack/stack.ghc-9.2+os-string.yaml b/stack/stack.ghc-9.2+os-string.yaml
new file mode 100644
index 0000000..d125405
--- /dev/null
+++ b/stack/stack.ghc-9.2+os-string.yaml
@@ -0,0 +1,19 @@
+resolver: lts-20.26
+
+extra-deps:
+  - hashable-1.4.7.0
+  - base64-1.0@sha256:ab8084608505f30d6cf7dd790271f927fd8a00956c5e7f5546f5cf56b298022c,2991
+  - directory-1.3.8.5@sha256:fbeec9ec346e5272167f63dcb86af513b457a7b9fc36dc818e4c7b81608d612b,3166
+  - filepath-1.5.3.0@sha256:0c64bc9a4f5946c86a8f0527bf40c8ba51e2c02d36eea0e20ea558c8d94166e8,4945
+  - os-string-2.0.6@sha256:7699e7ae9bf74d056a62f384ceef8dfb2aa660f3f7c8016e9703f3b995e5e030,3259
+  - process-1.6.21.0@sha256:685bc68759da31b5f152092fe664e1644e84f6dc0ae7a6c143e8564a1d6dafe8,2644
+  - text-2.0.2@sha256:71b5fa8c64d3c1fd0a08f993463220867b08290a2256e94b0952bf0e8f5a45cc,9905
+  - unix-2.8.5.1@sha256:3f702a252a313a7bcb56e3908a14e7f9f1b40e41b7bdc8ae8a9605a1a8686f06,9808
+
+flags:
+  directory:
+    os-string: true
+  os-string-aeson:
+    os-string: true
+  unix:
+    os-string: true
diff --git a/stack/stack.ghc-9.2+os-string.yaml.lock b/stack/stack.ghc-9.2+os-string.yaml.lock
new file mode 100644
index 0000000..5f47605
--- /dev/null
+++ b/stack/stack.ghc-9.2+os-string.yaml.lock
@@ -0,0 +1,68 @@
+# This file was autogenerated by Stack.
+# You should not edit this file by hand.
+# For more information, please see the documentation at:
+#   https://docs.haskellstack.org/en/stable/lock_files
+
+packages:
+- completed:
+    hackage: hashable-1.4.7.0@sha256:573f3ab242f75465a0d67ce9d84202650a1606575e6dbd6d31ffcf4767a9a379,6629
+    pantry-tree:
+      sha256: 9ec168505c52fa389b7447a1251b302e32537adeecac88c2aa72beed53beb3bd
+      size: 1578
+  original:
+    hackage: hashable-1.4.7.0
+- completed:
+    hackage: base64-1.0@sha256:ab8084608505f30d6cf7dd790271f927fd8a00956c5e7f5546f5cf56b298022c,2991
+    pantry-tree:
+      sha256: 62150ae24db8e07f966679024406de4cdfe13556c9afce807f4f24d7ec03d0b5
+      size: 2229
+  original:
+    hackage: base64-1.0@sha256:ab8084608505f30d6cf7dd790271f927fd8a00956c5e7f5546f5cf56b298022c,2991
+- completed:
+    hackage: directory-1.3.8.5@sha256:fbeec9ec346e5272167f63dcb86af513b457a7b9fc36dc818e4c7b81608d612b,3166
+    pantry-tree:
+      sha256: d11130a0ca9e7c8720ed1ceef4e2f0d9be4b446e67e7d15d634763a5c952877e
+      size: 3519
+  original:
+    hackage: directory-1.3.8.5@sha256:fbeec9ec346e5272167f63dcb86af513b457a7b9fc36dc818e4c7b81608d612b,3166
+- completed:
+    hackage: filepath-1.5.3.0@sha256:0c64bc9a4f5946c86a8f0527bf40c8ba51e2c02d36eea0e20ea558c8d94166e8,4945
+    pantry-tree:
+      sha256: a5feb33f17ff131a5bba009abae35761594d62ba6873b2f70992a48db160c9b7
+      size: 2274
+  original:
+    hackage: filepath-1.5.3.0@sha256:0c64bc9a4f5946c86a8f0527bf40c8ba51e2c02d36eea0e20ea558c8d94166e8,4945
+- completed:
+    hackage: os-string-2.0.6@sha256:7699e7ae9bf74d056a62f384ceef8dfb2aa660f3f7c8016e9703f3b995e5e030,3259
+    pantry-tree:
+      sha256: 4743363ed98362a8541108a2e7febb7ba32acd337d29dbff4472fafbe246589c
+      size: 2218
+  original:
+    hackage: os-string-2.0.6@sha256:7699e7ae9bf74d056a62f384ceef8dfb2aa660f3f7c8016e9703f3b995e5e030,3259
+- completed:
+    hackage: process-1.6.21.0@sha256:685bc68759da31b5f152092fe664e1644e84f6dc0ae7a6c143e8564a1d6dafe8,2644
+    pantry-tree:
+      sha256: 20d200008cf22d2f0402f900e0f26df17e355947689784852a10c28f03fbbca0
+      size: 1790
+  original:
+    hackage: process-1.6.21.0@sha256:685bc68759da31b5f152092fe664e1644e84f6dc0ae7a6c143e8564a1d6dafe8,2644
+- completed:
+    hackage: text-2.0.2@sha256:71b5fa8c64d3c1fd0a08f993463220867b08290a2256e94b0952bf0e8f5a45cc,9905
+    pantry-tree:
+      sha256: 25f3b6dd211e30f9e0ef5047bb9f30df7a9296cf1043873e31558196dfe78676
+      size: 7514
+  original:
+    hackage: text-2.0.2@sha256:71b5fa8c64d3c1fd0a08f993463220867b08290a2256e94b0952bf0e8f5a45cc,9905
+- completed:
+    hackage: unix-2.8.5.1@sha256:3f702a252a313a7bcb56e3908a14e7f9f1b40e41b7bdc8ae8a9605a1a8686f06,9808
+    pantry-tree:
+      sha256: b961320db69795a16c4ef4eebb0a3e7ddbbbe506fa1e22dde95ee8d8501bfbe5
+      size: 5821
+  original:
+    hackage: unix-2.8.5.1@sha256:3f702a252a313a7bcb56e3908a14e7f9f1b40e41b7bdc8ae8a9605a1a8686f06,9808
+snapshots:
+- completed:
+    sha256: 5a59b2a405b3aba3c00188453be172b85893cab8ebc352b1ef58b0eae5d248a2
+    size: 650475
+    url: https://raw.githubusercontent.com/commercialhaskell/stackage-snapshots/master/lts/20/26.yaml
+  original: lts-20.26
diff --git a/stack.ghc-9.2+old.yaml b/stack/stack.ghc-9.2.yaml
similarity index 93%
rename from stack.ghc-9.2+old.yaml
rename to stack/stack.ghc-9.2.yaml
index af21c38..723fdd8 100644
--- a/stack.ghc-9.2+old.yaml
+++ b/stack/stack.ghc-9.2.yaml
@@ -9,9 +9,5 @@ extra-deps:
   - text-2.0.2@sha256:71b5fa8c64d3c1fd0a08f993463220867b08290a2256e94b0952bf0e8f5a45cc,9905
   - unix-2.8.5.1@sha256:3f702a252a313a7bcb56e3908a14e7f9f1b40e41b7bdc8ae8a9605a1a8686f06,9808
 
-flags:
-  os-string-aeson:
-    old-os-string: true
-
 ghc-options:
   os-string-aeson: -Wno-deprecations
diff --git a/stack.ghc-9.2+old.yaml.lock b/stack/stack.ghc-9.2.yaml.lock
similarity index 100%
rename from stack.ghc-9.2+old.yaml.lock
rename to stack/stack.ghc-9.2.yaml.lock
diff --git a/stack/stack.ghc-9.4+os-string.yaml b/stack/stack.ghc-9.4+os-string.yaml
new file mode 100644
index 0000000..fa0a8c1
--- /dev/null
+++ b/stack/stack.ghc-9.4+os-string.yaml
@@ -0,0 +1,18 @@
+resolver: lts-21.25
+
+extra-deps:
+  - hashable-1.4.7.0
+  - base64-1.0@sha256:ab8084608505f30d6cf7dd790271f927fd8a00956c5e7f5546f5cf56b298022c,2991
+  - directory-1.3.8.5@sha256:fbeec9ec346e5272167f63dcb86af513b457a7b9fc36dc818e4c7b81608d612b,3166
+  - filepath-1.5.3.0@sha256:0c64bc9a4f5946c86a8f0527bf40c8ba51e2c02d36eea0e20ea558c8d94166e8,4945
+  - os-string-2.0.6@sha256:7699e7ae9bf74d056a62f384ceef8dfb2aa660f3f7c8016e9703f3b995e5e030,3259
+  - process-1.6.21.0@sha256:685bc68759da31b5f152092fe664e1644e84f6dc0ae7a6c143e8564a1d6dafe8,2644
+  - unix-2.8.5.1@sha256:3f702a252a313a7bcb56e3908a14e7f9f1b40e41b7bdc8ae8a9605a1a8686f06,9808
+
+flags:
+  directory:
+    os-string: true
+  os-string-aeson:
+    os-string: true
+  unix:
+    os-string: true
diff --git a/stack/stack.ghc-9.4+os-string.yaml.lock b/stack/stack.ghc-9.4+os-string.yaml.lock
new file mode 100644
index 0000000..fca4663
--- /dev/null
+++ b/stack/stack.ghc-9.4+os-string.yaml.lock
@@ -0,0 +1,61 @@
+# This file was autogenerated by Stack.
+# You should not edit this file by hand.
+# For more information, please see the documentation at:
+#   https://docs.haskellstack.org/en/stable/lock_files
+
+packages:
+- completed:
+    hackage: hashable-1.4.7.0@sha256:573f3ab242f75465a0d67ce9d84202650a1606575e6dbd6d31ffcf4767a9a379,6629
+    pantry-tree:
+      sha256: 9ec168505c52fa389b7447a1251b302e32537adeecac88c2aa72beed53beb3bd
+      size: 1578
+  original:
+    hackage: hashable-1.4.7.0
+- completed:
+    hackage: base64-1.0@sha256:ab8084608505f30d6cf7dd790271f927fd8a00956c5e7f5546f5cf56b298022c,2991
+    pantry-tree:
+      sha256: 62150ae24db8e07f966679024406de4cdfe13556c9afce807f4f24d7ec03d0b5
+      size: 2229
+  original:
+    hackage: base64-1.0@sha256:ab8084608505f30d6cf7dd790271f927fd8a00956c5e7f5546f5cf56b298022c,2991
+- completed:
+    hackage: directory-1.3.8.5@sha256:fbeec9ec346e5272167f63dcb86af513b457a7b9fc36dc818e4c7b81608d612b,3166
+    pantry-tree:
+      sha256: d11130a0ca9e7c8720ed1ceef4e2f0d9be4b446e67e7d15d634763a5c952877e
+      size: 3519
+  original:
+    hackage: directory-1.3.8.5@sha256:fbeec9ec346e5272167f63dcb86af513b457a7b9fc36dc818e4c7b81608d612b,3166
+- completed:
+    hackage: filepath-1.5.3.0@sha256:0c64bc9a4f5946c86a8f0527bf40c8ba51e2c02d36eea0e20ea558c8d94166e8,4945
+    pantry-tree:
+      sha256: a5feb33f17ff131a5bba009abae35761594d62ba6873b2f70992a48db160c9b7
+      size: 2274
+  original:
+    hackage: filepath-1.5.3.0@sha256:0c64bc9a4f5946c86a8f0527bf40c8ba51e2c02d36eea0e20ea558c8d94166e8,4945
+- completed:
+    hackage: os-string-2.0.6@sha256:7699e7ae9bf74d056a62f384ceef8dfb2aa660f3f7c8016e9703f3b995e5e030,3259
+    pantry-tree:
+      sha256: 4743363ed98362a8541108a2e7febb7ba32acd337d29dbff4472fafbe246589c
+      size: 2218
+  original:
+    hackage: os-string-2.0.6@sha256:7699e7ae9bf74d056a62f384ceef8dfb2aa660f3f7c8016e9703f3b995e5e030,3259
+- completed:
+    hackage: process-1.6.21.0@sha256:685bc68759da31b5f152092fe664e1644e84f6dc0ae7a6c143e8564a1d6dafe8,2644
+    pantry-tree:
+      sha256: 20d200008cf22d2f0402f900e0f26df17e355947689784852a10c28f03fbbca0
+      size: 1790
+  original:
+    hackage: process-1.6.21.0@sha256:685bc68759da31b5f152092fe664e1644e84f6dc0ae7a6c143e8564a1d6dafe8,2644
+- completed:
+    hackage: unix-2.8.5.1@sha256:3f702a252a313a7bcb56e3908a14e7f9f1b40e41b7bdc8ae8a9605a1a8686f06,9808
+    pantry-tree:
+      sha256: b961320db69795a16c4ef4eebb0a3e7ddbbbe506fa1e22dde95ee8d8501bfbe5
+      size: 5821
+  original:
+    hackage: unix-2.8.5.1@sha256:3f702a252a313a7bcb56e3908a14e7f9f1b40e41b7bdc8ae8a9605a1a8686f06,9808
+snapshots:
+- completed:
+    sha256: a81fb3877c4f9031e1325eb3935122e608d80715dc16b586eb11ddbff8671ecd
+    size: 640086
+    url: https://raw.githubusercontent.com/commercialhaskell/stackage-snapshots/master/lts/21/25.yaml
+  original: lts-21.25
diff --git a/stack.ghc-9.4+old.yaml b/stack/stack.ghc-9.4.yaml
similarity index 92%
rename from stack.ghc-9.4+old.yaml
rename to stack/stack.ghc-9.4.yaml
index 467f237..56940d0 100644
--- a/stack.ghc-9.4+old.yaml
+++ b/stack/stack.ghc-9.4.yaml
@@ -8,9 +8,5 @@ extra-deps:
   - process-1.6.20.0@sha256:2a9393de33f18415fb8f4826957a87a94ffe8840ca8472a9b69dca6de45aca03,2790
   - unix-2.8.5.1@sha256:3f702a252a313a7bcb56e3908a14e7f9f1b40e41b7bdc8ae8a9605a1a8686f06,9808
 
-flags:
-  os-string-aeson:
-    old-os-string: true
-
 ghc-options:
   os-string-aeson: -Wno-deprecations
diff --git a/stack.ghc-9.4+old.yaml.lock b/stack/stack.ghc-9.4.yaml.lock
similarity index 100%
rename from stack.ghc-9.4+old.yaml.lock
rename to stack/stack.ghc-9.4.yaml.lock
diff --git a/stack/stack.ghc-9.6+os-string.yaml b/stack/stack.ghc-9.6+os-string.yaml
new file mode 100644
index 0000000..6d093fe
--- /dev/null
+++ b/stack/stack.ghc-9.6+os-string.yaml
@@ -0,0 +1,16 @@
+resolver: lts-22.31
+
+extra-deps:
+  - base64-1.0@sha256:ab8084608505f30d6cf7dd790271f927fd8a00956c5e7f5546f5cf56b298022c,2991
+  - directory-1.3.8.5@sha256:fbeec9ec346e5272167f63dcb86af513b457a7b9fc36dc818e4c7b81608d612b,3166
+  - filepath-1.5.3.0@sha256:0c64bc9a4f5946c86a8f0527bf40c8ba51e2c02d36eea0e20ea558c8d94166e8,4945
+  - process-1.6.21.0@sha256:685bc68759da31b5f152092fe664e1644e84f6dc0ae7a6c143e8564a1d6dafe8,2644
+  - unix-2.8.5.1@sha256:3f702a252a313a7bcb56e3908a14e7f9f1b40e41b7bdc8ae8a9605a1a8686f06,9808
+
+flags:
+  directory:
+    os-string: true
+  os-string-aeson:
+    os-string: true
+  unix:
+    os-string: true
diff --git a/stack/stack.ghc-9.6+os-string.yaml.lock b/stack/stack.ghc-9.6+os-string.yaml.lock
new file mode 100644
index 0000000..19d1cd0
--- /dev/null
+++ b/stack/stack.ghc-9.6+os-string.yaml.lock
@@ -0,0 +1,47 @@
+# This file was autogenerated by Stack.
+# You should not edit this file by hand.
+# For more information, please see the documentation at:
+#   https://docs.haskellstack.org/en/stable/lock_files
+
+packages:
+- completed:
+    hackage: base64-1.0@sha256:ab8084608505f30d6cf7dd790271f927fd8a00956c5e7f5546f5cf56b298022c,2991
+    pantry-tree:
+      sha256: 62150ae24db8e07f966679024406de4cdfe13556c9afce807f4f24d7ec03d0b5
+      size: 2229
+  original:
+    hackage: base64-1.0@sha256:ab8084608505f30d6cf7dd790271f927fd8a00956c5e7f5546f5cf56b298022c,2991
+- completed:
+    hackage: directory-1.3.8.5@sha256:fbeec9ec346e5272167f63dcb86af513b457a7b9fc36dc818e4c7b81608d612b,3166
+    pantry-tree:
+      sha256: d11130a0ca9e7c8720ed1ceef4e2f0d9be4b446e67e7d15d634763a5c952877e
+      size: 3519
+  original:
+    hackage: directory-1.3.8.5@sha256:fbeec9ec346e5272167f63dcb86af513b457a7b9fc36dc818e4c7b81608d612b,3166
+- completed:
+    hackage: filepath-1.5.3.0@sha256:0c64bc9a4f5946c86a8f0527bf40c8ba51e2c02d36eea0e20ea558c8d94166e8,4945
+    pantry-tree:
+      sha256: a5feb33f17ff131a5bba009abae35761594d62ba6873b2f70992a48db160c9b7
+      size: 2274
+  original:
+    hackage: filepath-1.5.3.0@sha256:0c64bc9a4f5946c86a8f0527bf40c8ba51e2c02d36eea0e20ea558c8d94166e8,4945
+- completed:
+    hackage: process-1.6.21.0@sha256:685bc68759da31b5f152092fe664e1644e84f6dc0ae7a6c143e8564a1d6dafe8,2644
+    pantry-tree:
+      sha256: 20d200008cf22d2f0402f900e0f26df17e355947689784852a10c28f03fbbca0
+      size: 1790
+  original:
+    hackage: process-1.6.21.0@sha256:685bc68759da31b5f152092fe664e1644e84f6dc0ae7a6c143e8564a1d6dafe8,2644
+- completed:
+    hackage: unix-2.8.5.1@sha256:3f702a252a313a7bcb56e3908a14e7f9f1b40e41b7bdc8ae8a9605a1a8686f06,9808
+    pantry-tree:
+      sha256: b961320db69795a16c4ef4eebb0a3e7ddbbbe506fa1e22dde95ee8d8501bfbe5
+      size: 5821
+  original:
+    hackage: unix-2.8.5.1@sha256:3f702a252a313a7bcb56e3908a14e7f9f1b40e41b7bdc8ae8a9605a1a8686f06,9808
+snapshots:
+- completed:
+    sha256: acaab6ca693211938d1542abcb1c83a2f298b9f6b571854a9d38febe39b6408e
+    size: 719577
+    url: https://raw.githubusercontent.com/commercialhaskell/stackage-snapshots/master/lts/22/31.yaml
+  original: lts-22.31
diff --git a/stack.ghc-9.6+old.yaml b/stack/stack.ghc-9.6.yaml
similarity index 87%
rename from stack.ghc-9.6+old.yaml
rename to stack/stack.ghc-9.6.yaml
index 1bd468e..9b14938 100644
--- a/stack.ghc-9.6+old.yaml
+++ b/stack/stack.ghc-9.6.yaml
@@ -9,9 +9,5 @@ extra-deps:
   - base64-1.0@sha256:ab8084608505f30d6cf7dd790271f927fd8a00956c5e7f5546f5cf56b298022c,2991
   - os-string-1.0.0@sha256:f1582da15c52761681da87d98c854a0db54049f34d59f74cfec4cc56ad8fbc05,1852
 
-flags:
-  os-string-aeson:
-    old-os-string: true
-
 ghc-options:
   os-string-aeson: -Wno-deprecations
diff --git a/stack.ghc-9.6+old.yaml.lock b/stack/stack.ghc-9.6.yaml.lock
similarity index 100%
rename from stack.ghc-9.6+old.yaml.lock
rename to stack/stack.ghc-9.6.yaml.lock
diff --git a/stack/test-stack.sh b/stack/test-stack.sh
new file mode 100755
index 0000000..6e595ea
--- /dev/null
+++ b/stack/test-stack.sh
@@ -0,0 +1,18 @@
+#!/usr/bin/env bash
+
+set -eu
+
+for version in '9.2' '9.4' '9.6'; do
+    for flag in '+os-string' ''; do
+        stack_yaml="stack/stack.ghc-${version}${flag}.yaml"
+        echo "### TESTING ${stack_yaml}"
+        rm -rf .stack-work stack.yaml stack.yaml.lock
+        cp "${stack_yaml}" stack.yaml
+        stack test --pedantic
+        cp stack.yaml.lock "${stack_yaml}.lock"
+    done
+done
+
+rm -rf .stack-work stack.yaml stack.yaml.lock
+ln -s "${stack_yaml}" stack.yaml
+ln -s "${stack_yaml}.lock" stack.yaml.lock