diff --git a/.github/workflows/elixir.yml b/.github/workflows/elixir.yml
index 08ca75da..f2e97e33 100644
--- a/.github/workflows/elixir.yml
+++ b/.github/workflows/elixir.yml
@@ -9,30 +9,44 @@ on:
 
 jobs:
   build:
+    runs-on: ubuntu-latest
 
-    name: Build and test
-    runs-on: ubuntu-20.04
+    env:
+      MIX_ENV: test
+
+    strategy:
+      matrix:
+        elixir: [1.18.4]
+        otp: [28.0.2]
 
     steps:
-    - uses: actions/checkout@v2
-    - name: System dependencies
-      run: |
-        sudo apt update
-        sudo apt install -y inotify-tools
-    - name: Set up Elixir
-      uses: erlef/setup-beam@988e02bfe678367a02564f65ca2e37726dc0268f
-      with:
-        elixir-version: '1.12.3' # Define the elixir version [required]
-        otp-version: '24.1' # Define the OTP version [required]
-    - name: Restore dependencies cache
-      uses: actions/cache@v2
-      with:
-        path: deps
-        key: ${{ runner.os }}-mix-${{ hashFiles('**/mix.lock') }}
-        restore-keys: ${{ runner.os }}-mix-
-    - name: Install dependencies
-      run: mix deps.get
-    - name: Run tests
-      run: mix test
-    - name: Run static analytics
-      run: mix credo suggest --all --strict
+      - uses: actions/checkout@v4
+      - name: System Dependencies
+        run: |
+          sudo apt update
+          sudo apt install -y inotify-tools
+      - name: Setup Elixir
+        uses: erlef/setup-beam@v1
+        with:
+          otp-version: ${{ matrix.otp }}
+          elixir-version: ${{ matrix.elixir }}
+      - name: Restore dependencies cache
+        uses: actions/cache@v4
+        with:
+          path: |
+            deps
+            _build
+          key: mix-${{ runner.os }}-${{matrix.elixir}}-${{matrix.otp}}-${{ hashFiles('**/mix.lock') }}
+          restore-keys: |
+            mix-${{ runner.os }}-${{matrix.elixir}}-${{matrix.otp}}-
+
+      - name: Install dependencies
+        run: mix deps.get
+      - name: Check code format
+        run: mix format --check-formatted
+      - name: Run static analysis
+        run: mix credo --strict
+      - name: Check for unneeded dependencies
+        run: mix deps.unlock --check-unused
+      - name: Run tests
+        run: mix test
diff --git a/CNAME b/CNAME
deleted file mode 100644
index adedccf5..00000000
--- a/CNAME
+++ /dev/null
@@ -1 +0,0 @@
-elixirkoans.io
diff --git a/LICENSE.md b/LICENSE.md
index 21701bcb..5d2a478b 100644
--- a/LICENSE.md
+++ b/LICENSE.md
@@ -1,6 +1,6 @@
 The MIT License
 
-Copyright (c) 2015  http://elixirkoans.io
+Copyright (c) 2015 Elixir Koans
 
 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal
diff --git a/lib/display.ex b/lib/display.ex
index 1f57c16f..95d8f427 100644
--- a/lib/display.ex
+++ b/lib/display.ex
@@ -22,7 +22,7 @@ defmodule Display do
   end
 
   def handle_call(:clear_screen, _from, %{clear_screen: true} = state) do
-    ANSI.clear <> ANSI.home |> IO.puts()
+    (ANSI.clear() <> ANSI.home()) |> IO.puts()
 
     {:reply, :ok, state}
   end
@@ -58,6 +58,7 @@ defmodule Display do
   defp format(failure, module, name) do
     progress_bar = ProgressBar.progress_bar(Tracker.summarize())
     progress_bar_underline = String.duplicate("-", String.length(progress_bar))
+
     """
     #{Intro.intro(module, Tracker.visited())}
     Now meditate upon #{format_module(module)}
diff --git a/lib/display/failure.ex b/lib/display/failure.ex
index 57f1e627..88845a1f 100644
--- a/lib/display/failure.ex
+++ b/lib/display/failure.ex
@@ -50,7 +50,7 @@ defmodule Display.Failure do
   end
 
   defp format_error(error) do
-    trace = System.stacktrace() |> Enum.take(2)
+    trace = Process.info(self(), :current_stacktrace) |> Enum.take(2)
     Paint.red(Exception.format(:error, error, trace))
   end
 
diff --git a/lib/display/intro.ex b/lib/display/intro.ex
index 32ce92d2..85a1c2cb 100644
--- a/lib/display/intro.ex
+++ b/lib/display/intro.ex
@@ -6,7 +6,7 @@ defmodule Display.Intro do
     if module in modules do
       ""
     else
-      show_intro(module.intro)
+      module.intro() |> show_intro()
     end
   end
 
diff --git a/lib/display/progress_bar.ex b/lib/display/progress_bar.ex
index 71c1cdc0..5fd81a04 100644
--- a/lib/display/progress_bar.ex
+++ b/lib/display/progress_bar.ex
@@ -6,7 +6,9 @@ defmodule Display.ProgressBar do
     arrow = calculate_progress(current, total) |> build_arrow
     progress_percentage = calculate_percentage(current, total)
 
-    "|" <> String.pad_trailing(arrow, @progress_bar_length) <> "| #{current} of #{total} -> #{progress_percentage}% complete"
+    "|" <>
+      String.pad_trailing(arrow, @progress_bar_length) <>
+      "| #{current} of #{total} -> #{progress_percentage}% complete"
   end
 
   defp calculate_progress(current, total) do
diff --git a/lib/elixir_koans.ex b/lib/elixir_koans.ex
index dcf857f7..e1dbffa1 100644
--- a/lib/elixir_koans.ex
+++ b/lib/elixir_koans.ex
@@ -3,13 +3,11 @@ defmodule ElixirKoans do
   use Application
 
   def start(_type, _args) do
-    import Supervisor.Spec
-
     children = [
-      worker(Display, []),
-      worker(Tracker, []),
-      worker(Runner, []),
-      worker(Watcher, [])
+      %{id: Display, start: {Display, :start_link, []}},
+      %{id: Tracker, start: {Tracker, :start_link, []}},
+      %{id: Runner, start: {Runner, :start_link, []}},
+      %{id: Watcher, start: {Watcher, :start_link, []}}
     ]
 
     opts = [strategy: :one_for_one, name: ElixirKoans.Supervisor]
diff --git a/lib/execute.ex b/lib/execute.ex
index 6c462738..aa8af363 100644
--- a/lib/execute.ex
+++ b/lib/execute.ex
@@ -1,7 +1,8 @@
 defmodule Execute do
   @moduledoc false
   def run_module(module, callback \\ fn _result, _module, _koan -> nil end) do
-    Enum.reduce_while(module.all_koans, :passed, fn koan, _ ->
+    module.all_koans()
+    |> Enum.reduce_while(:passed, fn koan, _ ->
       module
       |> run_koan(koan)
       |> hook(module, koan, callback)
diff --git a/lib/koans/03_numbers.ex b/lib/koans/03_numbers.ex
index 9fb3ab23..274923d7 100644
--- a/lib/koans/03_numbers.ex
+++ b/lib/koans/03_numbers.ex
@@ -110,7 +110,7 @@ defmodule Numbers do
   end
 
   koan "I want the first and last in the range" do
-    first..last = Range.new(1, 10)
+    first..last//_step = Range.new(1, 10)
 
     assert first == ___
     assert last == ___
@@ -124,11 +124,11 @@ defmodule Numbers do
     assert 0 in range == ___
   end
 
-  def is_range?(%Range{}), do: true
-  def is_range?(_), do: false
+  def range?(%Range{}), do: true
+  def range?(_), do: false
 
   koan "Is this a range?" do
-    assert is_range?(1..10) == ___
-    assert is_range?(0) == ___
+    assert range?(1..10) == ___
+    assert range?(0) == ___
   end
 end
diff --git a/lib/tracker.ex b/lib/tracker.ex
index 018dd83b..79c36df8 100644
--- a/lib/tracker.ex
+++ b/lib/tracker.ex
@@ -18,7 +18,7 @@ defmodule Tracker do
   def set_total(modules) do
     total =
       modules
-      |> Enum.flat_map(& &1.all_koans)
+      |> Enum.flat_map(& &1.all_koans())
       |> Enum.count()
 
     Agent.update(__MODULE__, fn _ -> %Tracker{total: total} end)
diff --git a/lib/watcher.ex b/lib/watcher.ex
index eadb9a38..bbef3e89 100644
--- a/lib/watcher.ex
+++ b/lib/watcher.ex
@@ -36,15 +36,8 @@ defmodule Watcher do
     end
   end
 
-  # Elixir 1.7 deprecates Code.load_file in favor of Code.compile_file. In
-  # order to avoid the depecation warnings while maintaining backwards
-  # compatibility, we check the sytem version and execute conditionally.
   defp portable_load_file(file) do
-    if Version.match?(System.version(), "~> 1.7") do
-      Code.compile_file(file)
-    else
-      Code.load_file(file)
-    end
+    Code.compile_file(file)
   end
 
   defp normalize(file) do
diff --git a/mix.exs b/mix.exs
index de880795..4c852a21 100644
--- a/mix.exs
+++ b/mix.exs
@@ -2,21 +2,24 @@ defmodule Koans.Mixfile do
   use Mix.Project
 
   def project do
-    [app: :elixir_koans,
-     version: "0.0.1",
-     elixir: ">= 1.3.0 and < 2.0.0",
-     elixirc_paths: elixirc_path(Mix.env),
-     deps: deps()]
+    [
+      app: :elixir_koans,
+      version: "0.0.1",
+      elixir: ">= 1.3.0 and < 2.0.0",
+      elixirc_paths: elixirc_path(Mix.env()),
+      deps: deps()
+    ]
   end
 
   def application do
-    [mod: {ElixirKoans, []},
-     applications: [:file_system, :logger]]
+    [mod: {ElixirKoans, []}, applications: [:file_system, :logger]]
   end
 
   defp deps do
-    [{:file_system, "~> 0.2"},
-    {:credo, "~> 1.7", only: [:dev, :test], runtime: false}]
+    [
+      {:file_system, "~> 1.1"},
+      {:credo, "~> 1.7", only: [:dev, :test], runtime: false}
+    ]
   end
 
   defp elixirc_path(:test), do: ["lib/", "test/support"]
diff --git a/mix.lock b/mix.lock
index 3acd1054..004414be 100644
--- a/mix.lock
+++ b/mix.lock
@@ -1,6 +1,6 @@
 %{
-  "bunt": {:hex, :bunt, "0.2.1", "e2d4792f7bc0ced7583ab54922808919518d0e57ee162901a16a1b6664ef3b14", [:mix], [], "hexpm", "a330bfb4245239787b15005e66ae6845c9cd524a288f0d141c148b02603777a5"},
-  "credo": {:hex, :credo, "1.7.1", "6e26bbcc9e22eefbff7e43188e69924e78818e2fe6282487d0703652bc20fd62", [:mix], [{:bunt, "~> 0.2.1", [hex: :bunt, repo: "hexpm", optional: false]}, {:file_system, "~> 0.2.8", [hex: :file_system, repo: "hexpm", optional: false]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: false]}], "hexpm", "e9871c6095a4c0381c89b6aa98bc6260a8ba6addccf7f6a53da8849c748a58a2"},
-  "file_system": {:hex, :file_system, "0.2.10", "fb082005a9cd1711c05b5248710f8826b02d7d1784e7c3451f9c1231d4fc162d", [:mix], [], "hexpm", "41195edbfb562a593726eda3b3e8b103a309b733ad25f3d642ba49696bf715dc"},
-  "jason": {:hex, :jason, "1.4.1", "af1504e35f629ddcdd6addb3513c3853991f694921b1b9368b0bd32beb9f1b63", [:mix], [{:decimal, "~> 1.0 or ~> 2.0", [hex: :decimal, repo: "hexpm", optional: true]}], "hexpm", "fbb01ecdfd565b56261302f7e1fcc27c4fb8f32d56eab74db621fc154604a7a1"},
+  "bunt": {:hex, :bunt, "1.0.0", "081c2c665f086849e6d57900292b3a161727ab40431219529f13c4ddcf3e7a44", [:mix], [], "hexpm", "dc5f86aa08a5f6fa6b8096f0735c4e76d54ae5c9fa2c143e5a1fc7c1cd9bb6b5"},
+  "credo": {:hex, :credo, "1.7.12", "9e3c20463de4b5f3f23721527fcaf16722ec815e70ff6c60b86412c695d426c1", [:mix], [{:bunt, "~> 0.2.1 or ~> 1.0", [hex: :bunt, repo: "hexpm", optional: false]}, {:file_system, "~> 0.2 or ~> 1.0", [hex: :file_system, repo: "hexpm", optional: false]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: false]}], "hexpm", "8493d45c656c5427d9c729235b99d498bd133421f3e0a683e5c1b561471291e5"},
+  "file_system": {:hex, :file_system, "1.1.0", "08d232062284546c6c34426997dd7ef6ec9f8bbd090eb91780283c9016840e8f", [:mix], [], "hexpm", "bfcf81244f416871f2a2e15c1b515287faa5db9c6bcf290222206d120b3d43f6"},
+  "jason": {:hex, :jason, "1.4.4", "b9226785a9aa77b6857ca22832cffa5d5011a667207eb2a0ad56adb5db443b8a", [:mix], [{:decimal, "~> 1.0 or ~> 2.0", [hex: :decimal, repo: "hexpm", optional: true]}], "hexpm", "c5eb0cab91f094599f94d55bc63409236a8ec69a21a67814529e8d5f6cc90b3b"},
 }
diff --git a/test/executor_test.exs b/test/executor_test.exs
index 629c1eea..7248f8f7 100644
--- a/test/executor_test.exs
+++ b/test/executor_test.exs
@@ -7,7 +7,7 @@ defmodule ExecuteTest do
 
   test "stops at the first failing koan" do
     {:failed, %{file: file, line: line}, SampleKoan, _name} = Execute.run_module(SampleKoan)
-    assert file == 'test/support/sample_koan.ex'
+    assert file == ~c'test/support/sample_koan.ex'
     assert line == 9
   end
 
diff --git a/test/test_helper.exs b/test/test_helper.exs
index b7c383e4..bad94561 100644
--- a/test/test_helper.exs
+++ b/test/test_helper.exs
@@ -6,7 +6,7 @@ defmodule TestHarness do
   import ExUnit.Assertions
 
   def test_all(module, answers) do
-    module.all_koans
+    module.all_koans()
     |> check_answer_count(answers, module)
     |> Enum.zip(answers)
     |> run_all(module)