diff --git a/Gemfile b/Gemfile
index 15bb0d62..62255bd8 100644
--- a/Gemfile
+++ b/Gemfile
@@ -1,6 +1,6 @@
 source 'https://rubygems.org'
 
-gem 'kafo', '~> 4.0'
+gem 'kafo', '~> 4.1'
 gem 'librarian-puppet'
 gem 'puppet', ENV.key?('PUPPET_VERSION') ? "~> #{ENV['PUPPET_VERSION']}" : '~> 6.0'
 if RUBY_VERSION < '2.1'
diff --git a/hooks/boot/01-kafo-hook-extensions.rb b/hooks/boot/01-kafo-hook-extensions.rb
index 98989b6b..fc752732 100644
--- a/hooks/boot/01-kafo-hook-extensions.rb
+++ b/hooks/boot/01-kafo-hook-extensions.rb
@@ -33,7 +33,7 @@ def ensure_packages(packages, state = 'installed')
 
   def apply_puppet_code(code)
     bin_path = Kafo::PuppetCommand.search_puppet_path('puppet')
-    Open3.capture3("echo \"#{code}\" | #{bin_path} apply --detailed-exitcodes")
+    Open3.capture3(*Kafo::PuppetCommand.format_command("echo \"#{code}\" | #{bin_path} apply --detailed-exitcodes"))
   end
 
   def fail_and_exit(message, code = 1)
diff --git a/spec/hook_context_spec.rb b/spec/hook_context_spec.rb
index e0102a8e..9d2d77b2 100644
--- a/spec/hook_context_spec.rb
+++ b/spec/hook_context_spec.rb
@@ -120,7 +120,7 @@
       end
 
       after do
-        expect(Kafo::PuppetCommand).to have_received(:search_puppet_path)
+        expect(Kafo::PuppetCommand).to have_received(:search_puppet_path).twice
       end
 
       context 'empty code' do
@@ -128,7 +128,7 @@
 
         specify do
           is_expected.to eq('result')
-          expect(Open3).to have_received(:capture3).with('echo "" | /bin/puppet apply --detailed-exitcodes')
+          expect(Open3).to have_received(:capture3).with(anything, 'echo "" | /bin/puppet apply --detailed-exitcodes', anything)
         end
       end
 
@@ -137,7 +137,7 @@
 
         specify do
           is_expected.to eq('result')
-          expect(Open3).to have_received(:capture3).with('echo "package { \'vim-enhanced\': ensure => installed }" | /bin/puppet apply --detailed-exitcodes')
+          expect(Open3).to have_received(:capture3).with(anything, 'echo "package { \'vim-enhanced\': ensure => installed }" | /bin/puppet apply --detailed-exitcodes', anything)
         end
       end
     end