diff --git a/Gemfile b/Gemfile
index 1571dd49..66a69c37 100644
--- a/Gemfile
+++ b/Gemfile
@@ -5,20 +5,13 @@ gemspec
 
 gem 'json_pure'
 
-if RUBY_VERSION < '2.1'
-  # Technically not needed, but avoids issues with bundler versions
-  gem 'rdoc', '< 5.0.0'
-elsif RUBY_VERSION < '2.2'
-  gem 'rdoc', '< 6.0.0'
-end
-
 if ENV['PUPPET_VERSION']
   gem 'puppet', "~> #{ENV['PUPPET_VERSION']}"
 else
   gem 'puppet', '>= 4.5.0', '< 8.0.0'
 end
 
-gem 'puppet-strings', RUBY_VERSION >= '2.1' ? '>= 1.2.1' : '~> 1.2.1'
+gem 'puppet-strings', '>= 1.2.1'
 
 group :puppet_module do
   gem 'metadata-json-lint'
diff --git a/lib/kafo/fact_writer.rb b/lib/kafo/fact_writer.rb
index e530cf52..85316ce1 100644
--- a/lib/kafo/fact_writer.rb
+++ b/lib/kafo/fact_writer.rb
@@ -14,10 +14,9 @@ def self.write_facts(facts, directory)
     end
 
     def self.wrapper
-      # Ruby 2.0 doesn't have <<~ heredocs
-      <<-WRAPPER
-      require 'yaml'
-      Facter.add(:kafo) { setcode { YAML.load_file(File.join(__dir__, '#{DATA_FILENAME}')) } }
+      <<~WRAPPER
+        require 'yaml'
+        Facter.add(:kafo) { setcode { YAML.load_file(File.join(__dir__, '#{DATA_FILENAME}')) } }
       WRAPPER
     end
   end
diff --git a/lib/kafo/kafo_configure.rb b/lib/kafo/kafo_configure.rb
index d0bfc8fd..41389c75 100644
--- a/lib/kafo/kafo_configure.rb
+++ b/lib/kafo/kafo_configure.rb
@@ -525,8 +525,8 @@ def run_installation
               @progress_bar.update(line) if @progress_bar
             end
           rescue Errno::EIO # we reach end of input
-            exit_status = PTY.check(pid, true) if PTY.respond_to?(:check) # ruby >= 1.9.2
-            if exit_status.nil? # process is still running or we have old ruby so we don't know
+            exit_status = PTY.check(pid, true)
+            if exit_status.nil? # process is still running
               begin
                 Process.wait(pid)
               rescue Errno::ECHILD # process could exit meanwhile so we rescue
@@ -535,7 +535,7 @@ def run_installation
             end
           end
         end
-      rescue PTY::ChildExited => e # could be raised by Process.wait on older ruby or by PTY.check
+      rescue PTY::ChildExited => e # could be raised by PTY.check
         self.class.exit_handler.exit_code = e.status.exitstatus
       end
 
@@ -564,11 +564,7 @@ def config_file
     end
 
     def normalize_encoding(line)
-      if line.respond_to?(:encode) && line.respond_to?(:valid_encoding?)
-        line.valid_encoding? ? line : line.encode('UTF-16be', :invalid => :replace, :replace => '?').encode('UTF-8')
-      else  # Ruby 1.8.7, doesn't worry about invalid encodings
-        line
-      end
+      line.valid_encoding? ? line : line.encode('UTF-16be', :invalid => :replace, :replace => '?').encode('UTF-8')
     end
   end
 end
diff --git a/test/kafo/fact_writer_test.rb b/test/kafo/fact_writer_test.rb
index 6a661f92..6c3ae86b 100644
--- a/test/kafo/fact_writer_test.rb
+++ b/test/kafo/fact_writer_test.rb
@@ -18,7 +18,7 @@ module Kafo
     end
 
     describe '#wrapper' do
-      specify { _(subject.wrapper).must_equal("      require 'yaml'\n      Facter.add(:kafo) { setcode { YAML.load_file(File.join(__dir__, 'kafo.yaml')) } }\n") }
+      specify { _(subject.wrapper).must_equal("require 'yaml'\nFacter.add(:kafo) { setcode { YAML.load_file(File.join(__dir__, 'kafo.yaml')) } }\n") }
     end
   end
 end