diff --git a/lib/simple_form/action_view_extensions/builder.rb b/lib/simple_form/action_view_extensions/builder.rb
index e888575c..28cc8323 100644
--- a/lib/simple_form/action_view_extensions/builder.rb
+++ b/lib/simple_form/action_view_extensions/builder.rb
@@ -142,7 +142,7 @@ module SimpleForm
         # server if all checkboxes are unchecked.
         hidden = template.hidden_field_tag("#{object_name}[#{attribute}][]", "", :id => nil)
 
-        wrap_rendered_collection(rendered_collection << hidden, options)
+        wrap_rendered_collection(rendered_collection + hidden, options)
       end
 
       # Wrapper for using simple form inside a default rails form.
diff --git a/lib/simple_form/inputs/boolean_input.rb b/lib/simple_form/inputs/boolean_input.rb
index 9e07d9ca..5f30e53e 100644
--- a/lib/simple_form/inputs/boolean_input.rb
+++ b/lib/simple_form/inputs/boolean_input.rb
@@ -3,7 +3,7 @@ module SimpleForm
     class BooleanInput < Base
       def input
         if nested_boolean_style?
-          build_hidden_field_for_checkbox <<
+          build_hidden_field_for_checkbox +
             template.label_tag(nil, :class => "checkbox") {
               build_check_box_without_hidden_field
             }
@@ -16,7 +16,7 @@ module SimpleForm
         if options[:label] == false
           input
         elsif nested_boolean_style?
-          build_hidden_field_for_checkbox <<
+          build_hidden_field_for_checkbox +
             @builder.label(label_target, label_html_options) {
               build_check_box_without_hidden_field + label_text
             }