diff --git a/.rubocop.yml b/.rubocop.yml
index 489ee3f..6ea1b5b 100644
--- a/.rubocop.yml
+++ b/.rubocop.yml
@@ -2,7 +2,7 @@ inherit_from:
   - .rubocop_todo.yml
 
 AllCops:
-  TargetRubyVersion: 2.2
+  TargetRubyVersion: 2.3
   TargetRailsVersion: 5.1
 
 Rails:
diff --git a/.rubocop_todo.yml b/.rubocop_todo.yml
index 77cfe68..8dc61ca 100644
--- a/.rubocop_todo.yml
+++ b/.rubocop_todo.yml
@@ -1,6 +1,6 @@
 # This configuration was generated by
 # `rubocop --auto-gen-config`
-# on 2018-01-07 04:56:11 +0100 using RuboCop version 0.52.1.
+# on 2018-05-05 02:13:49 +0200 using RuboCop version 0.54.0.
 # The point is for the user to remove these configuration records
 # one by one as the offenses are removed from the code base.
 # Note that changes in the inspected code, or installation of new
@@ -74,6 +74,21 @@ Metrics/ParameterLists:
 Metrics/PerceivedComplexity:
   Max: 13
 
+# Offense count: 4
+# Configuration parameters: MinNameLength, AllowNamesEndingInNumbers, AllowedNames, ForbiddenNames.
+# AllowedNames: io, id, to
+Naming/UncommunicativeMethodParamName:
+  Exclude:
+    - 'app/helpers/xen_compute_helper.rb'
+    - 'app/models/foreman_xen/xenserver.rb'
+
+# Offense count: 19
+# Cop supports --auto-correct.
+# Configuration parameters: EnforcedStyle.
+# SupportedStyles: when_needed, always, never
+Style/FrozenStringLiteralComment:
+  Enabled: false
+
 # Offense count: 9
 # Cop supports --auto-correct.
 # Configuration parameters: EnforcedStyle.
diff --git a/.travis.yml b/.travis.yml
index 8c3d2f9..920110c 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,8 +1,6 @@
 sudo: false
 language: ruby
 rvm:
-  - 2.1.5
-  - 2.2.3
   - 2.3.1
   - 2.4.2
   - 2.5.0
diff --git a/Gemfile b/Gemfile
index ee415dd..3d57dd7 100644
--- a/Gemfile
+++ b/Gemfile
@@ -2,4 +2,4 @@ source 'https://rubygems.org'
 
 gemspec
 
-gem 'rubocop', '~> 0.52.1', require: false
+gem 'rubocop', '~> 0.54.0', require: false
diff --git a/foreman_xen.gemspec b/foreman_xen.gemspec
index a1fb896..98c90d9 100644
--- a/foreman_xen.gemspec
+++ b/foreman_xen.gemspec
@@ -1,4 +1,4 @@
-$LOAD_PATH.push File.expand_path('../lib', __FILE__)
+$LOAD_PATH.push File.expand_path('lib', __dir__)
 
 # Maintain your gem's version:
 require 'foreman_xen/version'
diff --git a/lib/foreman_xen/engine.rb b/lib/foreman_xen/engine.rb
index 3babe27..3b76f05 100644
--- a/lib/foreman_xen/engine.rb
+++ b/lib/foreman_xen/engine.rb
@@ -9,7 +9,7 @@ class Engine < ::Rails::Engine
     engine_name 'foreman_xen'
 
     initializer 'foreman_xen.register_gettext', :after => :load_config_initializers do |app|
-      locale_dir    = File.join(File.expand_path('../../..', __FILE__), 'locale')
+      locale_dir    = File.join(File.expand_path('../..', __dir__), 'locale')
       locale_domain = 'foreman-xen'
 
       Foreman::Gettext::Support.add_text_domain locale_domain, locale_dir
@@ -43,8 +43,8 @@ class Engine < ::Rails::Engine
       begin
         # extend fog xen server and image models.
         require 'fog/compute/xen_server/models/server'
-        require File.expand_path('../../../app/models/concerns/fog_extensions/xenserver/server', __FILE__)
-        require File.expand_path('../../../app/models/concerns/foreman_xen/host_helper_extensions', __FILE__)
+        require File.expand_path('../../app/models/concerns/fog_extensions/xenserver/server', __dir__)
+        require File.expand_path('../../app/models/concerns/foreman_xen/host_helper_extensions', __dir__)
 
         Fog::Compute::XenServer::Server.send(:include, ::FogExtensions::Xenserver::Server)
         ::HostsHelper.send(:include, ForemanXen::HostHelperExtensions)
diff --git a/test/test_helper.rb b/test/test_helper.rb
index 63cb0c9..c404f18 100644
--- a/test/test_helper.rb
+++ b/test/test_helper.rb
@@ -1,7 +1,7 @@
 # Configure Rails Environment
 ENV['RAILS_ENV'] = 'test'
 
-require File.expand_path('../dummy/config/environment.rb', __FILE__)
+require File.expand_path('dummy/config/environment.rb', __dir__)
 require 'rails/test_help'
 
 Rails.backtrace_cleaner.remove_silencers!
@@ -11,5 +11,5 @@
 
 # Load fixtures from the engine
 if ActiveSupport::TestCase.method_defined?(:fixture_path=)
-  ActiveSupport::TestCase.fixture_path = File.expand_path('../fixtures', __FILE__)
+  ActiveSupport::TestCase.fixture_path = File.expand_path('fixtures', __dir__)
 end