diff --git a/README.rdoc b/README.rdoc
index cc3ef28..5dce0c4 100644
--- a/README.rdoc
+++ b/README.rdoc
@@ -76,18 +76,6 @@ Make your model(s) that can follow other models acts_as_follower
     ...
   end
 
-Extended setup:
-  # config/initializers/acts_as_follower.rb
-
-  # By default list of parent classes includes only `[ApplicationRecord, ActiveRecord::Base]`.
-  ActsAsFollower.custom_parent_classes = [CustomRecord]
-
-  # OR
-
-  ActsAsFollower.setup do |c|
-    c.custom_parent_classes = [...]
-  end
-
 ---
 
 === acts_as_follower methods
diff --git a/lib/acts_as_follower.rb b/lib/acts_as_follower.rb
index 1789c04..c9246b2 100644
--- a/lib/acts_as_follower.rb
+++ b/lib/acts_as_follower.rb
@@ -6,25 +6,5 @@ module ActsAsFollower
   autoload :FollowerLib,  'acts_as_follower/follower_lib'
   autoload :FollowScopes, 'acts_as_follower/follow_scopes'
 
-  def self.setup
-    @configuration ||= Configuration.new
-    yield @configuration if block_given?
-  end
-
-  def self.method_missing(method_name, *args, &block)
-    @configuration.respond_to?(method_name) ?
-        @configuration.send(method_name, *args, &block) : super
-  end
-
-  class Configuration
-    attr_accessor :custom_parent_classes
-
-    def initialize
-      @custom_parent_classes = []
-    end
-  end
-
-  setup
-
   require 'acts_as_follower/railtie' if defined?(Rails) && Rails::VERSION::MAJOR >= 3
 end
diff --git a/lib/acts_as_follower/follower_lib.rb b/lib/acts_as_follower/follower_lib.rb
index 7c7a3f6..57c1a90 100644
--- a/lib/acts_as_follower/follower_lib.rb
+++ b/lib/acts_as_follower/follower_lib.rb
@@ -3,14 +3,9 @@ module FollowerLib
 
     private
 
-    DEFAULT_PARENTS = [ApplicationRecord, ActiveRecord::Base]
-
     # Retrieves the parent class name if using STI.
     def parent_class_name(obj)
-      unless parent_classes.include?(obj.class.superclass)
-        return obj.class.base_class.name
-      end
-      obj.class.name
+      obj.class.base_class.name
     end
 
     def apply_options_to_scope(scope, options = {})
@@ -32,10 +27,5 @@ def apply_options_to_scope(scope, options = {})
       scope
     end
 
-    def parent_classes
-      return DEFAULT_PARENTS unless ActsAsFollower.custom_parent_classes
-
-      ActsAsFollower.custom_parent_classes + DEFAULT_PARENTS
-    end
   end
 end
diff --git a/test/follow_test.rb b/test/follow_test.rb
index 5100b27..2f99749 100644
--- a/test/follow_test.rb
+++ b/test/follow_test.rb
@@ -7,55 +7,4 @@ def test_assert_true_should_be_true
     assert true
   end
 
-  context "configuration with setters" do
-    should "contain custom parents" do
-      ActsAsFollower.custom_parent_classes = [CustomRecord]
-
-      assert_equal [CustomRecord], ActsAsFollower.custom_parent_classes
-    end
-  end
-
-  context "#setup" do
-    should "contain custom parents via setup" do
-      ActsAsFollower.setup do |c|
-        c.custom_parent_classes = [CustomRecord]
-      end
-
-      assert_equal [CustomRecord], ActsAsFollower.custom_parent_classes
-    end
-  end
-
-  context "with custom parents" do
-    setup do
-      @daddy = FactoryGirl.create(:daddy)
-      @mommy = FactoryGirl.create(:mommy)
-      @oasis = FactoryGirl.create(:oasis)
-      @metallica = FactoryGirl.create(:metallica)
-    end
-
-    should "be followed" do
-      ActsAsFollower.custom_parent_classes = [CustomRecord]
-
-      @daddy.follow(@mommy)
-      @daddy.follow(@metallica)
-      @mommy.follow(@oasis)
-      assert_equal true, @daddy.following?(@mommy)
-      assert_equal false, @mommy.following?(@daddy)
-      assert_equal true, @mommy.followed_by?(@daddy)
-      assert_equal false, @daddy.followed_by?(@mommy)
-      assert_equal true, @metallica.followed_by?(@daddy)
-      assert_equal true, @oasis.followed_by?(@mommy)
-      assert_equal true, @daddy.following?(@metallica)
-      assert_equal true, @mommy.following?(@oasis)
-    end
-
-    should "be not followed" do
-      ActsAsFollower.custom_parent_classes = []
-
-      @daddy.follow(@mommy)
-      @mommy.follow(@oasis)
-      assert_equal false, @daddy.following?(@mommy)
-      assert_equal false, @mommy.following?(@oasis)
-    end
-  end
 end