diff --git a/.travis.yml b/.travis.yml
index 4b9421f7ac..403777e333 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -5,12 +5,12 @@ notifications:
   email: false
 
 rvm:
-  - 2.4.0
+  - 2.4.1
 
 matrix:
   include:
     - rvm: 2.3.3
-      env: "RAILS_VERSION=4.2.8"
+      env: "RAILS_VERSION=5.1.0.rc2"
     - rvm: jruby-9.1.7.0
       env: "RAILS_VERSION=5.0.2 JRUBY_OPTS=\"-J-Xms512m -J-Xmx1024m\""
   allow_failures:
diff --git a/app/helpers/blacklight/render_partials_helper_behavior.rb b/app/helpers/blacklight/render_partials_helper_behavior.rb
index be829c9c46..51d828e542 100644
--- a/app/helpers/blacklight/render_partials_helper_behavior.rb
+++ b/app/helpers/blacklight/render_partials_helper_behavior.rb
@@ -109,20 +109,11 @@ def document_index_path_templates
   # @example
   #  type_field_to_partial_name(['a book-article'])
   #  => 'a_book_article'
-  if Rails.version >= '5.0.0'
-    def type_field_to_partial_name(_document, display_type)
-      # using "_" as sep. to more closely follow the views file naming conventions
-      # parameterize uses "-" as the default sep. which throws errors
-      underscore = '_'.freeze
-      Array(display_type).join(' '.freeze).tr('-'.freeze, underscore).parameterize(separator: underscore)
-    end
-  else
-    def type_field_to_partial_name(_document, display_type)
-      # using "_" as sep. to more closely follow the views file naming conventions
-      # parameterize uses "-" as the default sep. which throws errors
-      underscore = '_'.freeze
-      Array(display_type).join(' '.freeze).tr('-'.freeze, underscore).parameterize(underscore)
-    end
+  def type_field_to_partial_name(_document, display_type)
+    # using "_" as sep. to more closely follow the views file naming conventions
+    # parameterize uses "-" as the default sep. which throws errors
+    underscore = '_'.freeze
+    Array(display_type).join(' '.freeze).tr('-'.freeze, underscore).parameterize(separator: underscore)
   end
 
   ##
diff --git a/app/models/search.rb b/app/models/search.rb
index 6c4469c5c7..9260cffa75 100644
--- a/app/models/search.rb
+++ b/app/models/search.rb
@@ -1,8 +1,6 @@
 # frozen_string_literal: true
 class Search < ActiveRecord::Base
-  belongs_to_arguments = { optional: true } if Rails.version >= '5.0.0'
-
-  belongs_to :user, belongs_to_arguments
+  belongs_to :user, optional: true
 
   serialize :query_params
 
diff --git a/blacklight.gemspec b/blacklight.gemspec
index 35b8b2f1a3..9f87211764 100644
--- a/blacklight.gemspec
+++ b/blacklight.gemspec
@@ -25,7 +25,7 @@ Gem::Specification.new do |s|
 
   s.required_ruby_version = '~> 2.1'
 
-  s.add_dependency "rails", ">= 4.2", "< 6"
+  s.add_dependency "rails", "~> 5.0"
   s.add_dependency "globalid"
   s.add_dependency "nokogiri",  "~>1.6"     # XML Parser
   s.add_dependency "kaminari", ">= 0.15" # the pagination (page 1,2,3, etc..) of our search results
diff --git a/spec/helpers/blacklight/url_helper_behavior_spec.rb b/spec/helpers/blacklight/url_helper_behavior_spec.rb
index 239c43af3b..4f4120103a 100644
--- a/spec/helpers/blacklight/url_helper_behavior_spec.rb
+++ b/spec/helpers/blacklight/url_helper_behavior_spec.rb
@@ -110,11 +110,7 @@
 
     context "without current search context" do
       before do
-        if Rails.version >= '5.0.0'
-          controller.request.assign_parameters(Rails.application.routes, 'catalog', 'show', { id: '123' }, '/catalog/123', [:controller, :action, :id])
-        else
-          controller.request.assign_parameters(Rails.application.routes, 'catalog', 'show', id: '123')
-        end
+        controller.request.assign_parameters(Rails.application.routes, 'catalog', 'show', { id: '123' }, '/catalog/123', [:controller, :action, :id])
         allow(helper).to receive_messages(current_search_session: nil)
       end
 
diff --git a/spec/spec_helper.rb b/spec/spec_helper.rb
index ba2762be0f..1f238fa590 100644
--- a/spec/spec_helper.rb
+++ b/spec/spec_helper.rb
@@ -65,10 +65,6 @@
   config.include(ControllerLevelHelpers, type: :view)
   config.before(:each, type: :view) { initialize_controller_helpers(view) }
 
-  unless Rails.version > '5'
-    config.include BackportTest, type: :controller
-  end
-
   config.expect_with :rspec do |expectations|
     expectations.include_chain_clauses_in_custom_matcher_descriptions = true
   end
diff --git a/spec/support/backport_test.rb b/spec/support/backport_test.rb
deleted file mode 100644
index 842615ed36..0000000000
--- a/spec/support/backport_test.rb
+++ /dev/null
@@ -1,14 +0,0 @@
-# Backport the Rails 5 controller test methods to Rails 4
-module BackportTest
-  [:delete, :get, :post, :put, :patch].each do |http_action|
-    define_method(http_action) do |*args|
-      (action, rest) = *args
-      rest ||= {}
-      if rest[:xhr]
-        @request.env['HTTP_X_REQUESTED_WITH'] = 'XMLHttpRequest'
-        @request.env['HTTP_ACCEPT'] ||= [Mime::JS, Mime::HTML, Mime::XML, 'text/xml', Mime::ALL].join(', ')
-      end
-      super(action, rest[:params])
-    end
-  end
-end
diff --git a/spec/test_app_templates/Gemfile.extra b/spec/test_app_templates/Gemfile.extra
index 135cae4f1b..cd3004db52 100644
--- a/spec/test_app_templates/Gemfile.extra
+++ b/spec/test_app_templates/Gemfile.extra
@@ -1,3 +1 @@
-if ENV['RAILS_VERSION'].nil? || ENV['RAILS_VERSION'] =~ /^5\.0/ || ENV['RAILS_VERSION'] == 'edge'
-  gem 'rails-controller-testing'
-end
+gem 'rails-controller-testing'