README.md in postmark-rails-0.16.0 vs README.md in postmark-rails-0.17.0

@@ -12,14 +12,14 @@
 
 For Rails 2.3 please take a look at [version 0.4](https://github.com/wildbit/postmark-rails/tree/v0.4.2). It may miss some new features, but receives all required bug fixes and other support if needed.
 
 ## Configuring your Rails application
 
-Add `postmark-rails` to your Gemfile (change version numbers if needed) and run `bundle install`.
+Add `postmark-rails` to your Gemfile and run `bundle install`.
 
 ``` ruby
-gem 'postmark-rails', '~> 0.15.0'
+gem 'postmark-rails'
 ```
 
 Save your Postmark API token to [config/secrets.yml](http://guides.rubyonrails.org/4_1_release_notes.html#config-secrets-yml).
 
 ``` yaml
@@ -71,9 +71,28 @@
   def message_with_attachment
     attachments.inline['logo.png'] = File.read("/path/to/image") # Inline image
     attachments['42.jpg'] = File.read("/path/to/file") # Attached file
     mail(
       :subject              => 'hello',
+      :to                   => '[e-mail]',
+      :from                 => '[e-mail]'
+    )
+  end
+
+end
+```
+
+## Attaching metadata to messages
+
+Postmark supports [attaching metadata to messages](https://postmarkapp.com/support/article/1125-custom-metadata-faq-1). All metadata field values will be interpreted and returned in webhook payloads as strings.
+
+``` ruby
+class TestMailer < ActionMailer::Base
+
+  def message_with_metadata
+    metadata['foo'] = 'bar'
+    mail(
+      :subject              => 'meta hello',
       :to                   => '[e-mail]',
       :from                 => '[e-mail]'
     )
   end