diff --git a/.gitignore b/.gitignore
index ff303bf..b64e008 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,5 +1,6 @@
 build
 dist
+dist-newstyle
 result
 
 cabal.sandbox.config
diff --git a/nix/sources.json b/nix/sources.json
index 7b5ed3c..960d4b4 100644
--- a/nix/sources.json
+++ b/nix/sources.json
@@ -34,5 +34,41 @@
         "type": "tarball",
         "url": "https://github.com/NixOS/nixpkgs/archive/a3fa481cb683d619ab9e1a64877f3c0c5fd24f40.tar.gz",
         "url_template": "https://github.com/<owner>/<repo>/archive/<rev>.tar.gz"
+    },
+    "nixpkgs-19.03": {
+        "branch": "release-19.03",
+        "description": "Nix Packages collection",
+        "homepage": "",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "27aaaa5ba6923104a23bae75d323dc975390195e",
+        "sha256": "1fdzc6psj369bi9bybgm9vwl5c7sa4z6k2sdz95ypcpgcg3s12ql",
+        "type": "tarball",
+        "url": "https://github.com/NixOS/nixpkgs/archive/27aaaa5ba6923104a23bae75d323dc975390195e.tar.gz",
+        "url_template": "https://github.com/<owner>/<repo>/archive/<rev>.tar.gz"
+    },
+    "nixpkgs-19.09": {
+        "branch": "release-19.09",
+        "description": "Nix Packages collection",
+        "homepage": "",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "75f4ba05c63be3f147bcc2f7bd4ba1f029cedcb1",
+        "sha256": "157c64220lf825ll4c0cxsdwg7cxqdx4z559fdp7kpz0g6p8fhhr",
+        "type": "tarball",
+        "url": "https://github.com/NixOS/nixpkgs/archive/75f4ba05c63be3f147bcc2f7bd4ba1f029cedcb1.tar.gz",
+        "url_template": "https://github.com/<owner>/<repo>/archive/<rev>.tar.gz"
+    },
+    "nixpkgs-20.03": {
+        "branch": "release-20.03",
+        "description": "Nix Packages collection",
+        "homepage": "",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "462c6fe4b115804ea4d5bee7103c0f46ff9f9cfb",
+        "sha256": "0a4bdaxjrds6kyw9s3r2vbc96f7glgy5n03jk4zr5z8h3j4v2s81",
+        "type": "tarball",
+        "url": "https://github.com/NixOS/nixpkgs/archive/462c6fe4b115804ea4d5bee7103c0f46ff9f9cfb.tar.gz",
+        "url_template": "https://github.com/<owner>/<repo>/archive/<rev>.tar.gz"
     }
 }
diff --git a/shell.nix b/shell.nix
index ef28d9f..63942bf 100644
--- a/shell.nix
+++ b/shell.nix
@@ -2,9 +2,17 @@
 # License: GNU/GPLv3 https://raw.githubusercontent.com/unclechu/place-cursor-at/master/LICENSE
 
 let sources = import nix/sources.nix; in
-# Forwarded arguments
 args@
-{ pkgs ? import sources.nixpkgs {}
+{ pkgs ?
+    import sources."nixpkgs${
+      if nixpkgs-release == "20.09" then "" else "-${nixpkgs-release}"
+    }" {}
+
+# Tested with lower 19.03 and upper 20.09 pins.
+, nixpkgs-release ? "20.09" # One of: '20.09', '20.03', '19.09', '19.03'
+
+# It’s not provided in 19.03 for instance
+, yq-go ? (import sources.nixpkgs { inherit (pkgs) config; }).yq-go
 
 # Forwarded build options
 , __src ? null
@@ -16,6 +24,7 @@ args@
 # Local arguments
 , withCabal ? false
 , withStack ? false
+, withStackNixDependencies ? false
 , withPackageRepl ? false # Adds package library modules into GHCi REPL
 , withHoogle ? true
 , buildExecutable ? true
@@ -28,7 +37,7 @@ let
   hp = pkg.haskellPackages;
   name = pkg.haskellPackage.pname;
 
-  inherit (nix-utils) wrapExecutable;
+  inherit (nix-utils) esc wrapExecutable;
   pkgReplGhc = hp.ghcWithPackages (p: [p.${name}]);
 
   # Produces ‘PACKAGE-NAME-ghc’ and ‘PACKAGE-NAME-ghci’ files.
@@ -43,6 +52,34 @@ let
       (exe "ghci")
       (exe "ghc")
     ];
+
+  stackNixDependencies =
+    let
+      stackYamlFile = "${./stack.yaml}";
+      path = "nix.packages";
+
+      nixModule = pkgs.runCommand "${name}-stack-yaml-nix-packages" {} ''
+        set -Eeuo pipefail || exit
+        JSON=$(${esc yq-go}/bin/yq r -j -- ${esc stackYamlFile} ${esc path})
+
+        if [[ -z $JSON ]]; then
+          >&2 printf 'Failed to extract "%s" from "%s"!\n' \
+            ${esc path} ${esc stackYamlFile}
+          exit 1
+        fi
+
+        printf '%s' "$JSON" > "$out"
+      '';
+
+      attrPathToDerivation = x:
+        pkgs.lib.attrsets.getAttrFromPath (pkgs.lib.splitString "." x) pkgs;
+
+      attrPaths = builtins.fromJSON (builtins.readFile nixModule);
+    in
+      assert builtins.isList attrPaths;
+      assert builtins.length attrPaths > 0;
+      assert builtins.all builtins.isString attrPaths;
+      map attrPathToDerivation attrPaths;
 in
 hp.shellFor {
   packages = p: [
@@ -54,6 +91,7 @@ hp.shellFor {
   buildInputs =
     (if withCabal then [ hp.cabal-install ] else []) ++
     (if withStack then [ hp.stack ] else []) ++
+    (if withStackNixDependencies then stackNixDependencies else []) ++
     (if buildExecutable then [ hp.${name} ] else []) ++
     (if withPackageRepl then pkgRepl else []);
 }
diff --git a/src/place-cursor-at.hs b/src/place-cursor-at.hs
index c7e7b07..1c9301a 100755
--- a/src/place-cursor-at.hs
+++ b/src/place-cursor-at.hs
@@ -9,7 +9,7 @@
 {-# LANGUAGE UnicodeSyntax, BangPatterns, MultiWayIf, ViewPatterns, ScopedTypeVariables, GADTs #-}
 {-# LANGUAGE LambdaCase, DerivingStrategies, GeneralizedNewtypeDeriving #-}
 
-import Prelude.Unicode
+import Prelude.Unicode ((∘), (÷), (≡), (⧺), (∧), (≥))
 
 import Data.Bifunctor (first)
 import Data.Bits ((.|.))
@@ -582,3 +582,10 @@ mkDoneHandler = newEmptyMVar <&> \mvar → DoneApi
 (•) = flip (∘)
 infixl 9 •
 {-# INLINE (•) #-}
+
+-- This operator is provided by newer version of ‘base-unicode-symbols’.
+-- This adds support for older snaphots.
+(×) ∷ Num a ⇒ a → a → a
+(×) = (Prelude.*)
+infixl 7 ×
+{-# INLINE (×) #-}
diff --git a/stack.yaml b/stack.yaml
index 7b79dd3..3c83b0e 100644
--- a/stack.yaml
+++ b/stack.yaml
@@ -1,5 +1,24 @@
-# also tested with lts-14.27 (ghc 8.6.5)
-resolver: lts-16.6 # ghc 8.8.3
+# Also tested with lts-13.19 (ghc 8.6.4).
+#
+# Test older one using Nix:
+#   nix-shell \
+#     --argstr nixpkgs-release 19.03 \
+#     --arg buildExecutable false \
+#     --arg withStack true \
+#     --arg withStackNixDependencies true \
+#     --run '[[ $(ghc --numeric-version) == 8.6.4 ]] && \
+#       stack build --system-ghc --no-nix --resolver=lts-13.19 && \
+#       stack exec --system-ghc --no-nix --resolver=lts-13.19 \
+#       place-cursor-at'
+#
+# Test current one using Nix:
+#   nix-shell \
+#     --arg buildExecutable false \
+#     --arg withStack true \
+#     --run 'stack build --system-ghc && \
+#       stack exec --system-ghc -- place-cursor-at'
+#
+resolver: lts-17.6 # ghc 8.10.4
 
 system-ghc: false
 packages: [.]
diff --git a/stack.yaml.lock b/stack.yaml.lock
index 0d17c05..a0e9c1f 100644
--- a/stack.yaml.lock
+++ b/stack.yaml.lock
@@ -6,7 +6,7 @@
 packages: []
 snapshots:
 - completed:
-    size: 531718
-    url: https://raw.githubusercontent.com/commercialhaskell/stackage-snapshots/master/lts/16/6.yaml
-    sha256: 230a7266fc11f76222bd3bb68e9503ed11d553060a752f164bff6753ed03e271
-  original: lts-16.6
+    size: 565712
+    url: https://raw.githubusercontent.com/commercialhaskell/stackage-snapshots/master/lts/17/6.yaml
+    sha256: 4e5e581a709c88e3fe26a9ce8bf331435729bead762fb5c190064c6c5bb1b835
+  original: lts-17.6