diff --git a/.travis.yml b/.travis.yml
index cc09511..b72bae5 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,9 +1,14 @@
 language: ruby
 sudo: false
 cache: bundler
+before_install:
+  - gem update --system
+  - rvm @global do gem uninstall bundler -a -x
+  - rvm @global do gem install bundler -v 1.13.7
 script: 'bundle exec rake test:coverage --trace && bundle exec rubocop'
 rvm:
   - 2.3.3
+  - 2.4.0
   - ruby-head
   - jruby-9.1.6.0
   - jruby-head
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 134eee8..3b2c5bd 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,6 +1,15 @@
 # Hanami::Helpers
 View helpers for Ruby web applications
 
+## v1.0.0.beta1 (unreleased)
+### Added
+- [Luca Guidi] Official support for Ruby: MRI 2.4
+- [Marion Duprey] Introduced Form helper `fields_for_collection` to support arrays of nested fields
+
+## Fixed
+- [Ksenia Zalesnaya] Ensure radio buttons and selects to coerce the value to boolean before to decide if they should be checked or not.
+- [Anton Davydov] Escape form values to prevent XSS attacks
+
 ## v0.5.1 - 2016-12-19
 ### Fixed
 - [Alex Coles] Ensure `#form_for`'s `values:` to accept `Hanami::Entity` instances
diff --git a/lib/hanami/helpers/form_helper/form_builder.rb b/lib/hanami/helpers/form_helper/form_builder.rb
index 8356056..9bc90ee 100644
--- a/lib/hanami/helpers/form_helper/form_builder.rb
+++ b/lib/hanami/helpers/form_helper/form_builder.rb
@@ -198,7 +198,49 @@ def to_s
         def fields_for(name)
           current_name = @name
           @name        = _input_name(name)
-          yield
+          yield(name)
+        ensure
+          @name = current_name
+        end
+
+        # Nested collections
+        #
+        # Supports nesting for collections, with infinite
+        # levels of nesting.
+        #
+        # @param name [Symbol] the nested name, it's used to generate input
+        #   names, ids, and to lookup params to fill values.
+        #
+        # @example Basic usage
+        #   <%=
+        #     form_for :delivery, routes.deliveries_path do
+        #       text_field :customer_name
+        #
+        #       fields_for_collection :addresses do
+        #         text_field :street
+        #       end
+        #
+        #       submit 'Create'
+        #     end
+        #   %>
+        #
+        #   Output:
+        #     # <form action="/deliveries" method="POST" accept-charset="utf-8" id="delivery-form">
+        #     #   <input type="text" name="delivery[customer_name]" id="delivery-customer-name" value="">
+        #     #   <input type="text" name="delivery[addresses][][street]" id="delivery-address-0-street" value="">
+        #     #   <input type="text" name="delivery[addresses][][street]" id="delivery-address-1-street" value="">
+        #     #
+        #     #   <button type="submit">Create</button>
+        #     # </form>
+        #
+        def fields_for_collection(name, &block)
+          current_name = @name
+          base_value = _value(name)
+          @name = _input_name(name)
+
+          base_value.count.times do |index|
+            fields_for(index, &block)
+          end
         ensure
           @name = current_name
         end
@@ -678,7 +720,7 @@ def text_field(name, attributes = {})
         #   #  <input type="radio" name="book[category]" value="Non-Fiction" checked="checked">
         def radio_button(name, value, attributes = {})
           attributes = { type: :radio, name: _input_name(name), value: value }.merge(attributes)
-          attributes[:checked] = CHECKED if _value(name) == value
+          attributes[:checked] = CHECKED if _value(name).to_s == value.to_s
           input(attributes)
         end
 
@@ -957,10 +999,14 @@ def csrf_token
         # @api private
         # @since 0.2.0
         def _attributes(type, name, attributes)
-          { type: type, name: _input_name(name), id: _input_id(name), value: _value(name) }.merge(attributes)
+          attrs = { type: type, name: _displayed_input_name(name), id: _input_id(name), value: _value(name) }
+          attrs.merge!(attributes)
+          attrs[:value] = Hanami::Utils::Escape.html(attrs[:value])
+          attrs
         end
 
-        # Input <tt>name</tt> HTML attribute
+        # Full input name, used to construct the input
+        # attributes.
         #
         # @api private
         # @since 0.2.0
@@ -968,6 +1014,14 @@ def _input_name(name)
           "#{@name}[#{name}]"
         end
 
+        # Input <tt>name</tt> HTML attribute
+        #
+        # @api private
+        # @since 1.0.0.beta1
+        def _displayed_input_name(name)
+          _input_name(name).gsub(/\[\d+\]/, '[]')
+        end
+
         # Input <tt>id</tt> HTML attribute
         #
         # @api private
@@ -1047,7 +1101,7 @@ def _select_input_name(name, multiple)
         # rubocop:disable Metrics/PerceivedComplexity
         def _select_option_selected?(value, selected, input_value, multiple)
           value == selected || (multiple && (selected.is_a?(Array) && selected.include?(value))) ||
-            value == input_value || (multiple && (input_value.is_a?(Array) && input_value.include?(value)))
+            value.to_s == input_value.to_s || (multiple && (input_value.is_a?(Array) && input_value.include?(value)))
         end
         # rubocop:enable Metrics/PerceivedComplexity
         # rubocop:enable Metrics/CyclomaticComplexity
diff --git a/lib/hanami/helpers/form_helper/values.rb b/lib/hanami/helpers/form_helper/values.rb
index a7d4863..91535b6 100644
--- a/lib/hanami/helpers/form_helper/values.rb
+++ b/lib/hanami/helpers/form_helper/values.rb
@@ -36,6 +36,7 @@ def get(*keys)
         # @since 0.5.0
         # @api private
         def _get_from_params(*keys)
+          keys.map! { |key| key.to_s =~ /\A\d+\z/ ? key.to_s.to_i : key }
           @params.dig(*keys)
         end
 
@@ -47,15 +48,21 @@ def _get_from_values(*keys)
 
           tail.each do |k|
             break if result.nil?
-
-            result = case result
-                     when Utils::Hash, ::Hash        then result[k]
-                     when ->(r) { r.respond_to?(k) } then result.public_send(k)
-                     end
+            result = _dig(result, k)
           end
 
           result
         end
+
+        # @since 1.0.0.beta1
+        # @api private
+        def _dig(base, key)
+          case base
+          when Utils::Hash, ::Hash        then base[key]
+          when Array                      then base[key.to_s.to_i]
+          when ->(r) { r.respond_to?(key) } then base.public_send(key)
+          end
+        end
       end
     end
   end
diff --git a/test/fixtures.rb b/test/fixtures.rb
index c222020..0e64c18 100644
--- a/test/fixtures.rb
+++ b/test/fixtures.rb
@@ -384,6 +384,15 @@ def initialize(attributes = {})
   end
 end
 
+class Bill
+  attr_reader :id, :addresses
+
+  def initialize(attributes = {})
+    @id        = attributes[:id]
+    @addresses = attributes[:addresses]
+  end
+end
+
 class DeliveryParams < Hanami::Action::Params
   params do
     required(:delivery).schema do
@@ -395,6 +404,18 @@ class DeliveryParams < Hanami::Action::Params
   end
 end
 
+class BillParams < Hanami::Action::Params
+  params do
+    required(:bill).schema do
+      required(:addresses).each do
+        schema do
+          required(:street, :string).filled
+        end
+      end
+    end
+  end
+end
+
 class Session
   def initialize(values)
     @values = values.to_h
@@ -423,6 +444,10 @@ def delivery_path(attrs = {})
       _escape "/deliveries/#{attrs.fetch(:id)}"
     end
 
+    def bill_path(attrs = {})
+      _escape "/bills/#{attrs.fetch(:id)}"
+    end
+
     private
 
     def _escape(string)
@@ -494,6 +519,21 @@ def submit_label
         end
       end
     end
+
+    module Bills
+      class Edit
+        include TestView
+        template 'bills/edit'
+
+        def form
+          Form.new(:bill, routes.bill_path(id: bill.id), { bill: bill }, method: :patch)
+        end
+
+        def submit_label
+          'Update'
+        end
+      end
+    end
   end
 end
 
diff --git a/test/fixtures/templates/bills/edit.html.erb b/test/fixtures/templates/bills/edit.html.erb
new file mode 100644
index 0000000..aa1063a
--- /dev/null
+++ b/test/fixtures/templates/bills/edit.html.erb
@@ -0,0 +1,18 @@
+<%=
+  form_for(form, class: 'form-horizontal') do
+    fieldset do
+      legend 'Addresses'
+
+      fields_for_collection :addresses do |i|
+        div class: 'form-group' do
+          label :street
+          input_text :street, class: 'form-control', placeholder: 'Street', 'data-funky': "id-#{i}"
+        end
+      end
+
+      label :ensure_names
+    end
+
+    submit submit_label, class: 'btn btn-default'
+  end
+%>
diff --git a/test/form_helper_test.rb b/test/form_helper_test.rb
index 994ebe4..a330061 100644
--- a/test/form_helper_test.rb
+++ b/test/form_helper_test.rb
@@ -311,6 +311,18 @@
           actual.must_include %(<input type="checkbox" name="book[free_shipping]" id="book-free-shipping" value="true" checked="checked">)
         end
       end
+
+      describe 'checked_value is boolean' do
+        let(:params) { Hash[book: { free_shipping: 'true' }] }
+
+        it "renders with 'checked' attribute" do
+          actual = view.form_for(:book, action) do
+            check_box :free_shipping, checked_value: true
+          end.to_s
+
+          actual.must_include %(<input type="checkbox" name="book[free_shipping]" id="book-free-shipping" value="true" checked="checked">)
+        end
+      end
     end
 
     describe 'automatic values' do
@@ -1011,6 +1023,27 @@
       end
     end
 
+    describe 'without values' do
+      let(:book)   { Book.new(title: val) }
+      let(:val)    { '"DDD" Book' }
+
+      it 'renders with value' do
+        actual = view.form_for(:book, action) do
+          text_field :title
+        end.to_s
+
+        actual.must_include %(<input type="text" name="book[title]" id="book-title" value="">)
+      end
+
+      it "allows to override 'value' attribute" do
+        actual = view.form_for(:book, action) do
+          text_field :title, value: book.title
+        end.to_s
+
+        actual.must_include %(<input type="text" name="book[title]" id="book-title" value="&quot;DDD&quot; Book">)
+      end
+    end
+
     describe 'with filled params' do
       let(:params) { Hash[book: { percent_read: val }] }
       let(:val)    { 95 }
@@ -1398,16 +1431,32 @@
     end
 
     describe 'with filled params' do
-      let(:params) { Hash[book: { category: val }] }
-      let(:val)    { 'Non-Fiction' }
+      describe 'string value' do
+        let(:params) { Hash[book: { category: val }] }
+        let(:val)    { 'Non-Fiction' }
 
-      it 'renders with value' do
-        actual = view.form_for(:book, action) do
-          radio_button :category, 'Fiction'
-          radio_button :category, 'Non-Fiction'
-        end.to_s
+        it 'renders with value' do
+          actual = view.form_for(:book, action) do
+            radio_button :category, 'Fiction'
+            radio_button :category, 'Non-Fiction'
+          end.to_s
 
-        actual.must_include %(<input type="radio" name="book[category]" value="Fiction">\n<input type="radio" name="book[category]" value="Non-Fiction" checked="checked">)
+          actual.must_include %(<input type="radio" name="book[category]" value="Fiction">\n<input type="radio" name="book[category]" value="Non-Fiction" checked="checked">)
+        end
+      end
+
+      describe 'decimal value' do
+        let(:params) { Hash[book: { price: val }] }
+        let(:val)    { '20.0' }
+
+        it 'renders with value' do
+          actual = view.form_for(:book, action) do
+            radio_button :price, 10.0
+            radio_button :price, 20.0
+          end.to_s
+
+          actual.must_include %(<input type="radio" name="book[price]" value="10.0">\n<input type="radio" name="book[price]" value="20.0" checked="checked">)
+        end
       end
     end
   end
@@ -1580,15 +1629,31 @@
       end
 
       describe 'with filled params' do
-        let(:params) { Hash[book: { store: val }] }
-        let(:val)    { 'it' }
+        describe 'string values' do
+          let(:params) { Hash[book: { store: val }] }
+          let(:val)    { 'it' }
 
-        it 'renders with value' do
-          actual = view.form_for(:book, action) do
-            select :store, option_values, options: { prompt: 'Select a store' }
-          end.to_s
+          it 'renders with value' do
+            actual = view.form_for(:book, action) do
+              select :store, option_values, options: { prompt: 'Select a store' }
+            end.to_s
 
-          actual.must_include %(<select name="book[store]" id="book-store">\n<option>Select a store</option>\n<option value="it" selected="selected">Italy</option>\n<option value="us">United States</option>\n</select>)
+            actual.must_include %(<select name="book[store]" id="book-store">\n<option>Select a store</option>\n<option value="it" selected="selected">Italy</option>\n<option value="us">United States</option>\n</select>)
+          end
+        end
+
+        describe 'integer values' do
+          let(:values) { Hash['Brave new world' => 1, 'Solaris' => 2] }
+          let(:params) { Hash[bookshelf: { book: val }] }
+          let(:val)    { '1' }
+
+          it 'renders' do
+            actual = view.form_for(:bookshelf, action) do
+              select :book, values
+            end.to_s
+
+            actual.must_include %(<select name="bookshelf[book]" id="bookshelf-book">\n<option value="1" selected="selected">Brave new world</option>\n<option value="2">Solaris</option>\n</select>)
+          end
         end
       end
     end
diff --git a/test/html_helper/html_builder_test.rb b/test/html_helper/html_builder_test.rb
index 333c4cc..8f5f1b2 100644
--- a/test/html_helper/html_builder_test.rb
+++ b/test/html_helper/html_builder_test.rb
@@ -206,8 +206,8 @@
     end
 
     it 'renders multiple attributes' do
-      result = @builder.input('required' => true, 'something' => 'bar').to_s
-      result.must_equal('<input required="required" something="bar">')
+      result = @builder.input('required' => true, 'value' => 'Title "book"', 'something' => 'bar').to_s
+      result.must_equal('<input required="required" value="Title "book"" something="bar">')
     end
   end
 
diff --git a/test/integration/form_helper_test.rb b/test/integration/form_helper_test.rb
index 9fa0ea2..d13285b 100644
--- a/test/integration/form_helper_test.rb
+++ b/test/integration/form_helper_test.rb
@@ -89,4 +89,38 @@
       end
     end
   end
+
+  describe 'form with nested structures' do
+    describe 'first page load' do
+      before do
+        @address1 = Address.new(street: '5th Ave')
+        @address2 = Address.new(street: '4th Ave')
+        @bill     = Bill.new(id: 1, addresses: [@address1, @address2])
+        @params   = BillParams.new({})
+        @session  = Session.new(_csrf_token: 's14')
+
+        @actual   = FullStack::Views::Bills::Edit.render(format: :html, bill: @bill, params: @params, session: @session)
+      end
+
+      it 'renders the form' do
+        @actual.must_include %(<form action="/bills/#{@bill.id}" method="POST" accept-charset="utf-8" id="bill-form" class="form-horizontal">\n<input type="hidden" name="_method" value="PATCH">\n<input type="hidden" name="_csrf_token" value="#{@session[:_csrf_token]}">\n<fieldset>\n<legend>Addresses</legend>\n<div class="form-group">\n<label for="bill-addresses-0-street">Street</label>\n<input type="text" name="bill[addresses][][street]" id="bill-addresses-0-street" value="#{@address1.street}" class="form-control" placeholder="Street" data-funky="id-0">\n</div>\n<div class="form-group">\n<label for="bill-addresses-1-street">Street</label>\n<input type="text" name="bill[addresses][][street]" id="bill-addresses-1-street" value="#{@address2.street}" class="form-control" placeholder="Street" data-funky="id-1">\n</div>\n<label for="bill-ensure-names">Ensure names</label>\n</fieldset>\n<button type="submit" class="btn btn-default">Update</button>\n</form>\n)
+      end
+    end
+
+    describe 'after a failed submission' do
+      before do
+        @address1 = Address.new(street: '5th Ave')
+        @address2 = Address.new(street: '4th Ave')
+        @bill     = Bill.new(id: 1, addresses: [@address1, @address2])
+        @params   = BillParams.new(bill: { addresses: [{ street: 'Mulholland Drive' }, { street: 'Quaint Edge' }] })
+        @session  = Session.new(_csrf_token: 's14')
+
+        @actual   = FullStack::Views::Bills::Edit.render(format: :html, bill: @bill, params: @params, session: @session)
+      end
+
+      it 'renders the form' do
+        @actual.must_include %(<form action="/bills/#{@bill.id}" method="POST" accept-charset="utf-8" id="bill-form" class="form-horizontal">\n<input type="hidden" name="_method" value="PATCH">\n<input type="hidden" name="_csrf_token" value="#{@session[:_csrf_token]}">\n<fieldset>\n<legend>Addresses</legend>\n<div class="form-group">\n<label for="bill-addresses-0-street">Street</label>\n<input type="text" name="bill[addresses][][street]" id="bill-addresses-0-street" value="#{@params[:bill][:addresses][0][:street]}" class="form-control" placeholder="Street" data-funky="id-0">\n</div>\n<div class="form-group">\n<label for="bill-addresses-1-street">Street</label>\n<input type="text" name="bill[addresses][][street]" id="bill-addresses-1-street" value="#{@params[:bill][:addresses][1][:street]}" class="form-control" placeholder="Street" data-funky="id-1">\n</div>\n<label for="bill-ensure-names">Ensure names</label>\n</fieldset>\n<button type="submit" class="btn btn-default">Update</button>\n</form>\n)
+      end
+    end
+  end
 end