diff --git a/Gemfile.lock b/Gemfile.lock
index f36c04c..ef8d035 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -8,43 +8,43 @@ PATH
 GEM
   remote: https://rubygems.org/
   specs:
-    actioncable (5.2.0)
-      actionpack (= 5.2.0)
+    actioncable (5.2.1)
+      actionpack (= 5.2.1)
       nio4r (~> 2.0)
       websocket-driver (>= 0.6.1)
-    actionmailer (5.2.0)
-      actionpack (= 5.2.0)
-      actionview (= 5.2.0)
-      activejob (= 5.2.0)
+    actionmailer (5.2.1)
+      actionpack (= 5.2.1)
+      actionview (= 5.2.1)
+      activejob (= 5.2.1)
       mail (~> 2.5, >= 2.5.4)
       rails-dom-testing (~> 2.0)
-    actionpack (5.2.0)
-      actionview (= 5.2.0)
-      activesupport (= 5.2.0)
+    actionpack (5.2.1)
+      actionview (= 5.2.1)
+      activesupport (= 5.2.1)
       rack (~> 2.0)
       rack-test (>= 0.6.3)
       rails-dom-testing (~> 2.0)
       rails-html-sanitizer (~> 1.0, >= 1.0.2)
-    actionview (5.2.0)
-      activesupport (= 5.2.0)
+    actionview (5.2.1)
+      activesupport (= 5.2.1)
       builder (~> 3.1)
       erubi (~> 1.4)
       rails-dom-testing (~> 2.0)
       rails-html-sanitizer (~> 1.0, >= 1.0.3)
-    activejob (5.2.0)
-      activesupport (= 5.2.0)
+    activejob (5.2.1)
+      activesupport (= 5.2.1)
       globalid (>= 0.3.6)
-    activemodel (5.2.0)
-      activesupport (= 5.2.0)
-    activerecord (5.2.0)
-      activemodel (= 5.2.0)
-      activesupport (= 5.2.0)
+    activemodel (5.2.1)
+      activesupport (= 5.2.1)
+    activerecord (5.2.1)
+      activemodel (= 5.2.1)
+      activesupport (= 5.2.1)
       arel (>= 9.0)
-    activestorage (5.2.0)
-      actionpack (= 5.2.0)
-      activerecord (= 5.2.0)
+    activestorage (5.2.1)
+      actionpack (= 5.2.1)
+      activerecord (= 5.2.1)
       marcel (~> 0.3.1)
-    activesupport (5.2.0)
+    activesupport (5.2.1)
       concurrent-ruby (~> 1.0, >= 1.0.2)
       i18n (>= 0.7, < 2)
       minitest (~> 5.1)
@@ -56,7 +56,7 @@ GEM
     erubi (1.7.1)
     globalid (0.4.1)
       activesupport (>= 4.2.0)
-    i18n (1.0.1)
+    i18n (1.1.0)
       concurrent-ruby (~> 1.0)
     loofah (2.2.2)
       crass (~> 1.0.2)
@@ -67,41 +67,41 @@ GEM
       mimemagic (~> 0.3.2)
     method_source (0.9.0)
     mimemagic (0.3.2)
-    mini_mime (1.0.0)
+    mini_mime (1.0.1)
     mini_portile2 (2.3.0)
     minitest (5.11.3)
     nio4r (2.3.1)
-    nokogiri (1.8.3)
+    nokogiri (1.8.4)
       mini_portile2 (~> 2.3.0)
     rack (2.0.5)
-    rack-test (1.0.0)
+    rack-test (1.1.0)
       rack (>= 1.0, < 3)
-    rails (5.2.0)
-      actioncable (= 5.2.0)
-      actionmailer (= 5.2.0)
-      actionpack (= 5.2.0)
-      actionview (= 5.2.0)
-      activejob (= 5.2.0)
-      activemodel (= 5.2.0)
-      activerecord (= 5.2.0)
-      activestorage (= 5.2.0)
-      activesupport (= 5.2.0)
+    rails (5.2.1)
+      actioncable (= 5.2.1)
+      actionmailer (= 5.2.1)
+      actionpack (= 5.2.1)
+      actionview (= 5.2.1)
+      activejob (= 5.2.1)
+      activemodel (= 5.2.1)
+      activerecord (= 5.2.1)
+      activestorage (= 5.2.1)
+      activesupport (= 5.2.1)
       bundler (>= 1.3.0)
-      railties (= 5.2.0)
+      railties (= 5.2.1)
       sprockets-rails (>= 2.0.0)
     rails-dom-testing (2.0.3)
       activesupport (>= 4.2.0)
       nokogiri (>= 1.6)
     rails-html-sanitizer (1.0.4)
       loofah (~> 2.2, >= 2.2.2)
-    railties (5.2.0)
-      actionpack (= 5.2.0)
-      activesupport (= 5.2.0)
+    railties (5.2.1)
+      actionpack (= 5.2.1)
+      activesupport (= 5.2.1)
       method_source
       rake (>= 0.8.7)
-      thor (>= 0.18.1, < 2.0)
+      thor (>= 0.19.0, < 2.0)
     rake (12.3.1)
-    sprockets (3.7.1)
+    sprockets (3.7.2)
       concurrent-ruby (~> 1.0)
       rack (> 1, < 3)
     sprockets-rails (3.2.1)
diff --git a/lib/active_model/type.rb b/lib/active_model/type.rb
deleted file mode 100644
index 3932499..0000000
--- a/lib/active_model/type.rb
+++ /dev/null
@@ -1,53 +0,0 @@
-# frozen_string_literal: true
-
-require "active_model/type/helpers"
-require "active_model/type/value"
-
-require "active_model/type/big_integer"
-require "active_model/type/binary"
-require "active_model/type/boolean"
-require "active_model/type/date"
-require "active_model/type/date_time"
-require "active_model/type/decimal"
-require "active_model/type/float"
-require "active_model/type/immutable_string"
-require "active_model/type/integer"
-require "active_model/type/string"
-require "active_model/type/time"
-
-require "active_model/type/registry"
-
-module ActiveModel
-  module Type
-    @registry = Registry.new
-
-    class << self
-      attr_accessor :registry # :nodoc:
-
-      # Add a new type to the registry, allowing it to be get through ActiveModel::Type#lookup
-      def register(type_name, klass = nil, **options, &block)
-        registry.register(type_name, klass, **options, &block)
-      end
-
-      def lookup(*args, **kwargs) # :nodoc:
-        registry.lookup(*args, **kwargs)
-      end
-
-      def default_value # :nodoc:
-        @default_value ||= Value.new
-      end
-    end
-
-    register(:big_integer, Type::BigInteger)
-    register(:binary, Type::Binary)
-    register(:boolean, Type::Boolean)
-    register(:date, Type::Date)
-    register(:datetime, Type::DateTime)
-    register(:decimal, Type::Decimal)
-    register(:float, Type::Float)
-    register(:immutable_string, Type::ImmutableString)
-    register(:integer, Type::Integer)
-    register(:string, Type::String)
-    register(:time, Type::Time)
-  end
-end
diff --git a/lib/active_model/type/big_integer.rb b/lib/active_model/type/big_integer.rb
deleted file mode 100644
index 89e43bc..0000000
--- a/lib/active_model/type/big_integer.rb
+++ /dev/null
@@ -1,15 +0,0 @@
-# frozen_string_literal: true
-
-require "active_model/type/integer"
-
-module ActiveModel
-  module Type
-    class BigInteger < Integer # :nodoc:
-      private
-
-        def max_value
-          ::Float::INFINITY
-        end
-    end
-  end
-end
diff --git a/lib/active_model/type/binary.rb b/lib/active_model/type/binary.rb
deleted file mode 100644
index dc2eca1..0000000
--- a/lib/active_model/type/binary.rb
+++ /dev/null
@@ -1,52 +0,0 @@
-# frozen_string_literal: true
-
-module ActiveModel
-  module Type
-    class Binary < Value # :nodoc:
-      def type
-        :binary
-      end
-
-      def binary?
-        true
-      end
-
-      def cast(value)
-        if value.is_a?(Data)
-          value.to_s
-        else
-          super
-        end
-      end
-
-      def serialize(value)
-        return if value.nil?
-        Data.new(super)
-      end
-
-      def changed_in_place?(raw_old_value, value)
-        old_value = deserialize(raw_old_value)
-        old_value != value
-      end
-
-      class Data # :nodoc:
-        def initialize(value)
-          @value = value.to_s
-        end
-
-        def to_s
-          @value
-        end
-        alias_method :to_str, :to_s
-
-        def hex
-          @value.unpack("H*")[0]
-        end
-
-        def ==(other)
-          other == to_s || super
-        end
-      end
-    end
-  end
-end
diff --git a/lib/active_model/type/boolean.rb b/lib/active_model/type/boolean.rb
deleted file mode 100644
index c7f6451..0000000
--- a/lib/active_model/type/boolean.rb
+++ /dev/null
@@ -1,34 +0,0 @@
-# frozen_string_literal: true
-
-module ActiveModel
-  module Type
-    # == Active \Model \Type \Boolean
-    #
-    # A class that behaves like a boolean type, including rules for coercion of user input.
-    #
-    # === Coercion
-    # Values set from user input will first be coerced into the appropriate ruby type.
-    # Coercion behavior is roughly mapped to Ruby's boolean semantics.
-    #
-    # - "false", "f" , "0", +0+ or any other value in +FALSE_VALUES+ will be coerced to +false+
-    # - Empty strings are coerced to +nil+
-    # - All other values will be coerced to +true+
-    class Boolean < Value
-      FALSE_VALUES = [false, 0, "0", "f", "F", "false", "FALSE", "off", "OFF"].to_set
-
-      def type # :nodoc:
-        :boolean
-      end
-
-      private
-
-      def cast_value(value)
-        if value == ""
-          nil
-        else
-          !FALSE_VALUES.include?(value)
-        end
-      end
-    end
-  end
-end
diff --git a/lib/active_model/type/date.rb b/lib/active_model/type/date.rb
deleted file mode 100644
index 0ee26ae..0000000
--- a/lib/active_model/type/date.rb
+++ /dev/null
@@ -1,56 +0,0 @@
-# frozen_string_literal: true
-
-module ActiveModel
-  module Type
-    class Date < Value # :nodoc:
-      include Helpers::AcceptsMultiparameterTime.new
-
-      def type
-        :date
-      end
-
-      def serialize(value)
-        cast(value)
-      end
-
-      def type_cast_for_schema(value)
-        value.to_s(:db).inspect
-      end
-
-      private
-
-      def cast_value(value)
-        if value.is_a?(::String)
-          return if value.empty?
-          fast_string_to_date(value) || fallback_string_to_date(value)
-        elsif value.respond_to?(:to_date)
-          value.to_date
-        else
-          value
-        end
-      end
-
-      ISO_DATE = /\A(\d{4})-(\d\d)-(\d\d)\z/
-      def fast_string_to_date(string)
-        if string =~ ISO_DATE
-          new_date $1.to_i, $2.to_i, $3.to_i
-        end
-      end
-
-      def fallback_string_to_date(string)
-        new_date(*::Date._parse(string, false).values_at(:year, :mon, :mday))
-      end
-
-      def new_date(year, mon, mday)
-        if year && year != 0
-          ::Date.new(year, mon, mday) rescue nil
-        end
-      end
-
-      def value_from_multiparameter_assignment(*)
-        time = super
-        time && time.to_date
-      end
-    end
-  end
-end
diff --git a/lib/active_model/type/date_time.rb b/lib/active_model/type/date_time.rb
deleted file mode 100644
index b92fe79..0000000
--- a/lib/active_model/type/date_time.rb
+++ /dev/null
@@ -1,50 +0,0 @@
-# frozen_string_literal: true
-
-module ActiveModel
-  module Type
-    class DateTime < Value # :nodoc:
-      include Helpers::TimeValue
-      include Helpers::AcceptsMultiparameterTime.new(
-        defaults: { 4 => 0, 5 => 0 }
-      )
-
-      def type
-        :datetime
-      end
-
-      def serialize(value)
-        super(cast(value))
-      end
-
-      private
-
-      def cast_value(value)
-        return apply_seconds_precision(value) unless value.is_a?(::String)
-        return if value.empty?
-
-        fast_string_to_time(value) || fallback_string_to_time(value)
-      end
-
-      # '0.123456' -> 123456
-      # '1.123456' -> 123456
-      def microseconds(time)
-        time[:sec_fraction] ? (time[:sec_fraction] * 1_000_000).to_i : 0
-      end
-
-      def fallback_string_to_time(string)
-        time_hash = ::Date._parse(string)
-        time_hash[:sec_fraction] = microseconds(time_hash)
-
-        new_time(*time_hash.values_at(:year, :mon, :mday, :hour, :min, :sec, :sec_fraction, :offset))
-      end
-
-      def value_from_multiparameter_assignment(values_hash)
-        missing_parameter = (1..3).detect { |key| !values_hash.key?(key) }
-        if missing_parameter
-          raise ArgumentError, missing_parameter
-        end
-        super
-      end
-    end
-  end
-end
diff --git a/lib/active_model/type/decimal.rb b/lib/active_model/type/decimal.rb
deleted file mode 100644
index 12bf1d2..0000000
--- a/lib/active_model/type/decimal.rb
+++ /dev/null
@@ -1,70 +0,0 @@
-# frozen_string_literal: true
-
-require "bigdecimal/util"
-
-module ActiveModel
-  module Type
-    class Decimal < Value # :nodoc:
-      include Helpers::Numeric
-      BIGDECIMAL_PRECISION = 18
-
-      def type
-        :decimal
-      end
-
-      def type_cast_for_schema(value)
-        value.to_s.inspect
-      end
-
-      private
-
-      def cast_value(value)
-        casted_value = \
-          case value
-          when ::Float
-            convert_float_to_big_decimal(value)
-          when ::Numeric
-            BigDecimal(value, precision || BIGDECIMAL_PRECISION)
-          when ::String
-            begin
-              value.to_d
-            rescue ArgumentError
-              BigDecimal(0)
-            end
-          else
-            if value.respond_to?(:to_d)
-              value.to_d
-            else
-              cast_value(value.to_s)
-            end
-          end
-
-        apply_scale(casted_value)
-      end
-
-      def convert_float_to_big_decimal(value)
-        if precision
-          BigDecimal(apply_scale(value), float_precision)
-        else
-          value.to_d
-        end
-      end
-
-      def float_precision
-        if precision.to_i > ::Float::DIG + 1
-          ::Float::DIG + 1
-        else
-          precision.to_i
-        end
-      end
-
-      def apply_scale(value)
-        if scale
-          value.round(scale)
-        else
-          value
-        end
-      end
-    end
-  end
-end
diff --git a/lib/active_model/type/float.rb b/lib/active_model/type/float.rb
deleted file mode 100644
index b493f64..0000000
--- a/lib/active_model/type/float.rb
+++ /dev/null
@@ -1,36 +0,0 @@
-# frozen_string_literal: true
-
-module ActiveModel
-  module Type
-    class Float < Value # :nodoc:
-      include Helpers::Numeric
-
-      def type
-        :float
-      end
-
-      def type_cast_for_schema(value)
-        return "::Float::NAN" if value.try(:nan?)
-        case value
-        when ::Float::INFINITY then "::Float::INFINITY"
-        when -::Float::INFINITY then "-::Float::INFINITY"
-        else super
-        end
-      end
-
-      alias serialize cast
-
-      private
-
-      def cast_value(value)
-        case value
-        when ::Float then value
-        when "Infinity" then ::Float::INFINITY
-        when "-Infinity" then -::Float::INFINITY
-        when "NaN" then ::Float::NAN
-        else value.to_f
-        end
-      end
-    end
-  end
-end
diff --git a/lib/active_model/type/helpers.rb b/lib/active_model/type/helpers.rb
deleted file mode 100644
index 403f0a9..0000000
--- a/lib/active_model/type/helpers.rb
+++ /dev/null
@@ -1,6 +0,0 @@
-# frozen_string_literal: true
-
-require "active_model/type/helpers/accepts_multiparameter_time"
-require "active_model/type/helpers/numeric"
-require "active_model/type/helpers/mutable"
-require "active_model/type/helpers/time_value"
diff --git a/lib/active_model/type/helpers/accepts_multiparameter_time.rb b/lib/active_model/type/helpers/accepts_multiparameter_time.rb
deleted file mode 100644
index ad891f8..0000000
--- a/lib/active_model/type/helpers/accepts_multiparameter_time.rb
+++ /dev/null
@@ -1,41 +0,0 @@
-# frozen_string_literal: true
-
-module ActiveModel
-  module Type
-    module Helpers # :nodoc: all
-      class AcceptsMultiparameterTime < Module
-        def initialize(defaults: {})
-          define_method(:cast) do |value|
-            if value.is_a?(Hash)
-              value_from_multiparameter_assignment(value)
-            else
-              super(value)
-            end
-          end
-
-          define_method(:assert_valid_value) do |value|
-            if value.is_a?(Hash)
-              value_from_multiparameter_assignment(value)
-            else
-              super(value)
-            end
-          end
-
-          define_method(:value_constructed_by_mass_assignment?) do |value|
-            value.is_a?(Hash)
-          end
-
-          define_method(:value_from_multiparameter_assignment) do |values_hash|
-            defaults.each do |k, v|
-              values_hash[k] ||= v
-            end
-            return unless values_hash[1] && values_hash[2] && values_hash[3]
-            values = values_hash.sort.map(&:last)
-            ::Time.send(default_timezone, *values)
-          end
-          private :value_from_multiparameter_assignment
-        end
-      end
-    end
-  end
-end
diff --git a/lib/active_model/type/helpers/mutable.rb b/lib/active_model/type/helpers/mutable.rb
deleted file mode 100644
index 1cbea64..0000000
--- a/lib/active_model/type/helpers/mutable.rb
+++ /dev/null
@@ -1,20 +0,0 @@
-# frozen_string_literal: true
-
-module ActiveModel
-  module Type
-    module Helpers # :nodoc: all
-      module Mutable
-        def cast(value)
-          deserialize(serialize(value))
-        end
-
-        # +raw_old_value+ will be the `_before_type_cast` version of the
-        # value (likely a string). +new_value+ will be the current, type
-        # cast value.
-        def changed_in_place?(raw_old_value, new_value)
-          raw_old_value != serialize(new_value)
-        end
-      end
-    end
-  end
-end
diff --git a/lib/active_model/type/helpers/numeric.rb b/lib/active_model/type/helpers/numeric.rb
deleted file mode 100644
index bfb6692..0000000
--- a/lib/active_model/type/helpers/numeric.rb
+++ /dev/null
@@ -1,37 +0,0 @@
-# frozen_string_literal: true
-
-module ActiveModel
-  module Type
-    module Helpers # :nodoc: all
-      module Numeric
-        def cast(value)
-          value = \
-            case value
-            when true then 1
-            when false then 0
-            when ::String then value.presence
-            else value
-            end
-          super(value)
-        end
-
-        def changed?(old_value, _new_value, new_value_before_type_cast) # :nodoc:
-          super || number_to_non_number?(old_value, new_value_before_type_cast)
-        end
-
-        private
-
-        def number_to_non_number?(old_value, new_value_before_type_cast)
-          old_value != nil && non_numeric_string?(new_value_before_type_cast)
-        end
-
-        def non_numeric_string?(value)
-          # 'wibble'.to_i will give zero, we want to make sure
-          # that we aren't marking int zero to string zero as
-          # changed.
-          value.to_s !~ /\A-?\d+\.?\d*\z/
-        end
-      end
-    end
-  end
-end
diff --git a/lib/active_model/type/helpers/time_value.rb b/lib/active_model/type/helpers/time_value.rb
deleted file mode 100644
index 21613c7..0000000
--- a/lib/active_model/type/helpers/time_value.rb
+++ /dev/null
@@ -1,79 +0,0 @@
-# frozen_string_literal: true
-
-require "active_support/core_ext/time/zones"
-
-module ActiveModel
-  module Type
-    module Helpers # :nodoc: all
-      module TimeValue
-        def serialize(value)
-          value = apply_seconds_precision(value)
-
-          if value.acts_like?(:time)
-            zone_conversion_method = is_utc? ? :getutc : :getlocal
-
-            if value.respond_to?(zone_conversion_method)
-              value = value.send(zone_conversion_method)
-            end
-          end
-
-          value
-        end
-
-        def is_utc?
-          ::Time.zone_default.nil? || ::Time.zone_default =~ "UTC"
-        end
-
-        def default_timezone
-          if is_utc?
-            :utc
-          else
-            :local
-          end
-        end
-
-        def apply_seconds_precision(value)
-          return value unless precision && value.respond_to?(:usec)
-          number_of_insignificant_digits = 6 - precision
-          round_power = 10**number_of_insignificant_digits
-          value.change(usec: value.usec - value.usec % round_power)
-        end
-
-        def type_cast_for_schema(value)
-          value.to_s(:db).inspect
-        end
-
-        def user_input_in_time_zone(value)
-          value.in_time_zone
-        end
-
-        private
-
-        def new_time(year, mon, mday, hour, min, sec, microsec, offset = nil)
-          # Treat 0000-00-00 00:00:00 as nil.
-          return if year.nil? || (year == 0 && mon == 0 && mday == 0)
-
-          if offset
-            time = ::Time.utc(year, mon, mday, hour, min, sec, microsec) rescue nil
-            return unless time
-
-            time -= offset
-            is_utc? ? time : time.getlocal
-          else
-            ::Time.public_send(default_timezone, year, mon, mday, hour, min, sec, microsec) rescue nil
-          end
-        end
-
-        ISO_DATETIME = /\A(\d{4})-(\d\d)-(\d\d) (\d\d):(\d\d):(\d\d)(\.\d+)?\z/
-
-        # Doesn't handle time zones.
-        def fast_string_to_time(string)
-          if string =~ ISO_DATETIME
-            microsec = ($7.to_r * 1_000_000).to_i
-            new_time $1.to_i, $2.to_i, $3.to_i, $4.to_i, $5.to_i, $6.to_i, microsec
-          end
-        end
-      end
-    end
-  end
-end
diff --git a/lib/active_model/type/immutable_string.rb b/lib/active_model/type/immutable_string.rb
deleted file mode 100644
index ee380f9..0000000
--- a/lib/active_model/type/immutable_string.rb
+++ /dev/null
@@ -1,32 +0,0 @@
-# frozen_string_literal: true
-
-module ActiveModel
-  module Type
-    class ImmutableString < Value # :nodoc:
-      def type
-        :string
-      end
-
-      def serialize(value)
-        case value
-        when ::Numeric, ActiveSupport::Duration then value.to_s
-        when true then "t"
-        when false then "f"
-        else super
-        end
-      end
-
-      private
-
-      def cast_value(value)
-        result = \
-          case value
-          when true then "t"
-          when false then "f"
-          else value.to_s
-          end
-        result.freeze
-      end
-    end
-  end
-end
diff --git a/lib/active_model/type/integer.rb b/lib/active_model/type/integer.rb
deleted file mode 100644
index c90cd2c..0000000
--- a/lib/active_model/type/integer.rb
+++ /dev/null
@@ -1,70 +0,0 @@
-# frozen_string_literal: true
-
-module ActiveModel
-  module Type
-    class Integer < Value # :nodoc:
-      include Helpers::Numeric
-
-      # Column storage size in bytes.
-      # 4 bytes means an integer as opposed to smallint etc.
-      DEFAULT_LIMIT = 4
-
-      def initialize(*)
-        super
-        @range = min_value...max_value
-      end
-
-      def type
-        :integer
-      end
-
-      def deserialize(value)
-        return if value.nil?
-        value.to_i
-      end
-
-      def serialize(value)
-        result = cast(value)
-        if result
-          ensure_in_range(result)
-        end
-        result
-      end
-
-      # TODO Change this to private once we've dropped Ruby 2.2 support.
-      # Workaround for Ruby 2.2 "private attribute?" warning.
-      protected
-
-      attr_reader :range
-
-      private
-
-      def cast_value(value)
-        case value
-        when true then 1
-        when false then 0
-        else
-          value.to_i rescue nil
-        end
-      end
-
-      def ensure_in_range(value)
-        unless range.cover?(value)
-          raise ActiveModel::RangeError, "#{value} is out of range for #{self.class} with limit #{_limit} bytes"
-        end
-      end
-
-      def max_value
-        1 << (_limit * 8 - 1) # 8 bits per byte with one bit for sign
-      end
-
-      def min_value
-        -max_value
-      end
-
-      def _limit
-        limit || DEFAULT_LIMIT
-      end
-    end
-  end
-end
diff --git a/lib/active_model/type/registry.rb b/lib/active_model/type/registry.rb
deleted file mode 100644
index b2bc9e0..0000000
--- a/lib/active_model/type/registry.rb
+++ /dev/null
@@ -1,70 +0,0 @@
-# frozen_string_literal: true
-
-module ActiveModel
-  # :stopdoc:
-  module Type
-    class Registry
-      def initialize
-        @registrations = []
-      end
-
-      def register(type_name, klass = nil, **options, &block)
-        block ||= proc { |_, *args| klass.new(*args) }
-        registrations << registration_klass.new(type_name, block, **options)
-      end
-
-      def lookup(symbol, *args)
-        registration = find_registration(symbol, *args)
-
-        if registration
-          registration.call(self, symbol, *args)
-        else
-          raise ArgumentError, "Unknown type #{symbol.inspect}"
-        end
-      end
-
-      # TODO Change this to private once we've dropped Ruby 2.2 support.
-      # Workaround for Ruby 2.2 "private attribute?" warning.
-      protected
-
-      attr_reader :registrations
-
-      private
-
-      def registration_klass
-        Registration
-      end
-
-      def find_registration(symbol, *args)
-        registrations.find { |r| r.matches?(symbol, *args) }
-      end
-    end
-
-    class Registration
-      # Options must be taken because of https://bugs.ruby-lang.org/issues/10856
-      def initialize(name, block, **)
-        @name = name
-        @block = block
-      end
-
-      def call(_registry, *args, **kwargs)
-        if kwargs.any? # https://bugs.ruby-lang.org/issues/10856
-          block.call(*args, **kwargs)
-        else
-          block.call(*args)
-        end
-      end
-
-      def matches?(type_name, *args, **kwargs)
-        type_name == name
-      end
-
-      # TODO Change this to private once we've dropped Ruby 2.2 support.
-      # Workaround for Ruby 2.2 "private attribute?" warning.
-      protected
-
-      attr_reader :name, :block
-    end
-  end
-  # :startdoc:
-end
diff --git a/lib/active_model/type/string.rb b/lib/active_model/type/string.rb
deleted file mode 100644
index 031b548..0000000
--- a/lib/active_model/type/string.rb
+++ /dev/null
@@ -1,26 +0,0 @@
-# frozen_string_literal: true
-
-require "active_model/type/immutable_string"
-
-module ActiveModel
-  module Type
-    class String < ImmutableString # :nodoc:
-      def changed_in_place?(raw_old_value, new_value)
-        if new_value.is_a?(::String)
-          raw_old_value != new_value
-        end
-      end
-
-      private
-
-      def cast_value(value)
-        case value
-        when ::String then ::String.new(value)
-        when true then "t".freeze
-        when false then "f".freeze
-        else value.to_s
-        end
-      end
-    end
-  end
-end
diff --git a/lib/active_model/type/time.rb b/lib/active_model/type/time.rb
deleted file mode 100644
index bc068c7..0000000
--- a/lib/active_model/type/time.rb
+++ /dev/null
@@ -1,48 +0,0 @@
-# frozen_string_literal: true
-
-module ActiveModel
-  module Type
-    class Time < Value # :nodoc:
-      include Helpers::TimeValue
-      include Helpers::AcceptsMultiparameterTime.new(
-        defaults: { 1 => 1970, 2 => 1, 3 => 1, 4 => 0, 5 => 0 }
-      )
-
-      def type
-        :time
-      end
-
-      def user_input_in_time_zone(value)
-        return unless value.present?
-
-        case value
-        when ::String
-          value = "2000-01-01 #{value}"
-        when ::Time
-          value = value.change(year: 2000, day: 1, month: 1)
-        end
-
-        super(value)
-      end
-
-      private
-
-      def cast_value(value)
-        return value unless value.is_a?(::String)
-        return if value.empty?
-
-        if value.start_with?("2000-01-01")
-          dummy_time_value = value
-        else
-          dummy_time_value = "2000-01-01 #{value}"
-        end
-
-        fast_string_to_time(dummy_time_value) || begin
-          time_hash = ::Date._parse(dummy_time_value)
-          return if time_hash[:hour].nil?
-          new_time(*time_hash.values_at(:year, :mon, :mday, :hour, :min, :sec, :sec_fraction, :offset))
-        end
-      end
-    end
-  end
-end
diff --git a/lib/active_model/type/value.rb b/lib/active_model/type/value.rb
deleted file mode 100644
index cb0bece..0000000
--- a/lib/active_model/type/value.rb
+++ /dev/null
@@ -1,122 +0,0 @@
-# frozen_string_literal: true
-
-module ActiveModel
-  module Type
-    class Value
-      attr_reader :precision, :scale, :limit
-
-      def initialize(precision: nil, limit: nil, scale: nil)
-        @precision = precision
-        @scale = scale
-        @limit = limit
-      end
-
-      def type # :nodoc:
-      end
-
-      # Converts a value from database input to the appropriate ruby type. The
-      # return value of this method will be returned from
-      # ActiveRecord::AttributeMethods::Read#read_attribute. The default
-      # implementation just calls Value#cast.
-      #
-      # +value+ The raw input, as provided from the database.
-      def deserialize(value)
-        cast(value)
-      end
-
-      # Type casts a value from user input (e.g. from a setter). This value may
-      # be a string from the form builder, or a ruby object passed to a setter.
-      # There is currently no way to differentiate between which source it came
-      # from.
-      #
-      # The return value of this method will be returned from
-      # ActiveRecord::AttributeMethods::Read#read_attribute. See also:
-      # Value#cast_value.
-      #
-      # +value+ The raw input, as provided to the attribute setter.
-      def cast(value)
-        cast_value(value) unless value.nil?
-      end
-
-      # Casts a value from the ruby type to a type that the database knows how
-      # to understand. The returned value from this method should be a
-      # +String+, +Numeric+, +Date+, +Time+, +Symbol+, +true+, +false+, or
-      # +nil+.
-      def serialize(value)
-        value
-      end
-
-      # Type casts a value for schema dumping. This method is private, as we are
-      # hoping to remove it entirely.
-      def type_cast_for_schema(value) # :nodoc:
-        value.inspect
-      end
-
-      # These predicates are not documented, as I need to look further into
-      # their use, and see if they can be removed entirely.
-      def binary? # :nodoc:
-        false
-      end
-
-      # Determines whether a value has changed for dirty checking. +old_value+
-      # and +new_value+ will always be type-cast. Types should not need to
-      # override this method.
-      def changed?(old_value, new_value, _new_value_before_type_cast)
-        old_value != new_value
-      end
-
-      # Determines whether the mutable value has been modified since it was
-      # read. Returns +false+ by default. If your type returns an object
-      # which could be mutated, you should override this method. You will need
-      # to either:
-      #
-      # - pass +new_value+ to Value#serialize and compare it to
-      #   +raw_old_value+
-      #
-      # or
-      #
-      # - pass +raw_old_value+ to Value#deserialize and compare it to
-      #   +new_value+
-      #
-      # +raw_old_value+ The original value, before being passed to
-      # +deserialize+.
-      #
-      # +new_value+ The current value, after type casting.
-      def changed_in_place?(raw_old_value, new_value)
-        false
-      end
-
-      def value_constructed_by_mass_assignment?(_value) # :nodoc:
-        false
-      end
-
-      def map(value) # :nodoc:
-        yield value
-      end
-
-      def ==(other)
-        self.class == other.class &&
-          precision == other.precision &&
-          scale == other.scale &&
-          limit == other.limit
-      end
-      alias eql? ==
-
-      def hash
-        [self.class, precision, scale, limit].hash
-      end
-
-      def assert_valid_value(*)
-      end
-
-      private
-
-      # Convenience method for types which do not need separate type casting
-      # behavior for user and database inputs. Called by Value#cast for
-      # values except +nil+.
-      def cast_value(value) # :doc:
-        value
-      end
-    end
-  end
-end
diff --git a/lib/options_model.rb b/lib/options_model.rb
index 4ce4f02..c79205b 100644
--- a/lib/options_model.rb
+++ b/lib/options_model.rb
@@ -9,9 +9,5 @@
 
 require "options_model/base"
 
-if ActiveModel.gem_version < Gem::Version.new("5.0.0")
-  require "active_model/type"
-end
-
 module OptionsModel
 end
diff --git a/options_model.gemspec b/options_model.gemspec
index 2ddc96f..1e2c43c 100644
--- a/options_model.gemspec
+++ b/options_model.gemspec
@@ -21,8 +21,8 @@ Gem::Specification.new do |s|
 
   s.files   = Dir["{app,config,db,lib}/**/*", "MIT-LICENSE", "Rakefile", "README.md"]
 
-  s.add_dependency "activemodel", ">= 4.2", "< 6.0"
-  s.add_dependency "activesupport", ">= 4.2", "< 6.0"
+  s.add_dependency "activemodel", ">= 5", "< 6.0"
+  s.add_dependency "activesupport", ">= 5", "< 6.0"
 
   s.add_development_dependency "rails", "~> 5.0"
 end