diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 523c7785..4e88c7f3 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -1,16 +1,61 @@
 name: CI
-on: [push]
+on:
+  pull_request:
+  push:
+    branches:
+      - master
+      - main
+  schedule:
+    - cron: '0 9 1 * *'
+
 jobs:
+  koans:
+    strategy:
+      fail-fast: false
+      matrix:
+        ruby:
+          - '2.0'
+          - '2.1'
+          - '2.2'
+          - '2.3'
+          - '2.4'
+          - '2.5'
+          - '2.6'
+          - '2.7'
+          - '3.0'
+          - '3.1'
+          - '3.2'
+          - '3.3'
+          - '3.4'
+          - '4.0'
+          - ruby-head
+        os: [ubuntu-latest]
+        include:
+          - ruby: '1.9'
+            os: ubuntu-22.04
+    runs-on: ${{ matrix.os }}
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v7
+
+      - name: Install Ruby!
+        uses: ruby/setup-ruby@v1
+        with:
+          ruby-version: ${{ matrix.ruby }}
+
+      - name: Run solved koans
+        run: rake run
+
   test:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout code
-        uses: actions/checkout@v3
+        uses: actions/checkout@v7
 
       - name: Install Ruby!
         uses: ruby/setup-ruby@v1
         with:
-          ruby-version: "3.2.2"
+          ruby-version: '4.0'
 
       - name: run tests
-        run: rake test
\ No newline at end of file
+        run: rake test
diff --git a/rakelib/checks.rake b/rakelib/checks.rake
index c1b20d7d..c5cd2e6a 100644
--- a/rakelib/checks.rake
+++ b/rakelib/checks.rake
@@ -19,10 +19,10 @@ namespace "check" do
   task :asserts do
     puts "Checking for asserts missing the replacement text:"
     begin
-      sh "egrep -n 'assert( |_)' src/about_*.rb | egrep -v '__|_n_|project|about_assert' | egrep -v ' *#'"
+      sh "grep -En 'assert( |_)' src/about_*.rb | grep -Ev '__|_n_|project|about_assert' | grep -Ev ' *#'"
       puts
       puts "Examine the above lines for missing __ replacements"
-    rescue RuntimeError => ex
+    rescue RuntimeError
       puts "OK"
     end
     puts
diff --git a/src/Rakefile b/src/Rakefile
index 1a2c7f26..69212630 100644
--- a/src/Rakefile
+++ b/src/Rakefile
@@ -7,6 +7,8 @@ require 'rake/testtask'
 task :default => :test
 
 task :test do
-  ruby 'path_to_enlightenment.rb'
+  ruby 'path_to_enlightenment.rb' do |ok, res|
+    exit res.exitstatus unless ok
+  end
 end
 
diff --git a/src/about_keyword_arguments.rb b/src/about_keyword_arguments.rb
index 3c9856b9..2ee443da 100644
--- a/src/about_keyword_arguments.rb
+++ b/src/about_keyword_arguments.rb
@@ -37,7 +37,7 @@ def test_mandatory_keyword_arguments_without_mandatory_argument
     exception = assert_raise(___(ArgumentError)) do
       method_with_mandatory_keyword_arguments
     end
-    assert_match(/#{__("missing keyword: :one")}/, exception.message)
+    assert_match(/#{__("missing keyword: :?one")}/, exception.message)
   end
 
 end
diff --git a/src/neo.rb b/src/neo.rb
index 0985362a..a9a4224f 100644
--- a/src/neo.rb
+++ b/src/neo.rb
@@ -26,7 +26,7 @@ def in_ruby_version(*versions)
 end
 
 def before_ruby_version(version)
-  Gem::Version.new(RUBY_VERSION) < Gem::Version.new(version)
+  Gem::Version.new(RUBY_VERSION.dup) < Gem::Version.new(version)
 end
 
 in_ruby_version("1.8") do
@@ -519,6 +519,7 @@ def walk
         sensei.observe(step.meditate)
       end
       sensei.instruct
+      !sensei.failed?
     end
 
     def each_step
@@ -536,6 +537,8 @@ def each_step
 end
 
 END {
+  exception = $!
+
   Neo::Koan.command_line(ARGV)
-  Neo::ThePath.new.walk
+  exit exception.nil? && Neo::ThePath.new.walk
 }
diff --git a/src/path_to_enlightenment.rb b/src/path_to_enlightenment.rb
index aacf7cfb..210b3550 100644
--- a/src/path_to_enlightenment.rb
+++ b/src/path_to_enlightenment.rb
@@ -12,7 +12,7 @@
 require 'about_nil'
 require 'about_hashes'
 require 'about_methods'
-in_ruby_version("2", "3", "4") do
+in_ruby_version("2.[1-7]", "3", "4") do
   require 'about_keyword_arguments'
 end
 require 'about_constants'