3 files changed, 55 insertions, 16 deletions

diff --git a/guides/source/action_mailer_basics.md b/guides/source/action_mailer_basics.md
index 041a427f7c..1acb993cad 100644
--- a/guides/source/action_mailer_basics.md
+++ b/guides/source/action_mailer_basics.md
@@ -839,13 +839,14 @@ Mailer Testing
 You can find detailed instructions on how to test your mailers in the
 [testing guide](testing.html#testing-your-mailers).
 
-Intercepting Emails
+Intercepting and Observing Emails
 -------------------
 
-There are situations where you need to edit an email before it's
-delivered. Fortunately Action Mailer provides hooks to intercept every
-email. You can register an interceptor to make modifications to mail messages
-right before they are handed to the delivery agents.
+Action Mailer provides hooks into the Mail observer and interceptor methods. These allow you to register classes that are called during the mail delivery life cycle of every email sent.
+
+### Intercepting Emails
+
+Interceptors allow you to make modifications to emails before they are handed off to the delivery agents. An interceptor class must implement the `:delivering_email(message)` method which will be called before the email is sent.
 
 ```ruby
 class SandboxEmailInterceptor
@@ -869,3 +870,21 @@ NOTE: The example above uses a custom environment called "staging" for a
 production like server but for testing purposes. You can read
 [Creating Rails environments](configuring.html#creating-rails-environments)
 for more information about custom Rails environments.
+
+### Observing Emails
+
+Observers give you access to the email message after it has been sent. An observer class must implement the `:delivered_email(message)` method, which will be called after the email is sent.
+
+```ruby
+class EmailDeliveryObserver
+  def self.delivered_email(message)
+    EmailDelivery.log(message)
+  end
+end
+```
+Like interceptors, you need to register observers with the Action Mailer framework. You can do this in an initializer file 
+`config/initializers/email_delivery_observer.rb`
+
+```ruby
+ActionMailer::Base.register_observer(EmailDeliveryObserver)
+```
diff --git a/guides/source/documents.yaml b/guides/source/documents.yaml
index 551179c523..25c159d471 100644
--- a/guides/source/documents.yaml
+++ b/guides/source/documents.yaml
@@ -207,46 +207,46 @@
       url: 6_0_release_notes.html
       description: Release notes for Rails 6.0.
     -
-      name: 5.2 Release Notes
+      name: Version 5.2 - April 2018
       url: 5_2_release_notes.html
       description: Release notes for Rails 5.2.
     -
-      name: 5.1 Release Notes
+      name: Version 5.1 - April 2017
       url: 5_1_release_notes.html
       description: Release notes for Rails 5.1.
     -
-      name: 5.0 Release Notes
+      name: Version 5.0 - June 2016
       url: 5_0_release_notes.html
       description: Release notes for Rails 5.0.
     -
-      name: 4.2 Release Notes
+      name: Version 4.2 - December 2014
       url: 4_2_release_notes.html
       description: Release notes for Rails 4.2.
     -
-      name: 4.1 Release Notes
+      name: Version 4.1 - April 2014
       url: 4_1_release_notes.html
       description: Release notes for Rails 4.1.
     -
-      name: 4.0 Release Notes
+      name: Version 4.0 - June 2013
       url: 4_0_release_notes.html
       description: Release notes for Rails 4.0.
     -
-      name: 3.2 Release Notes
+      name: Version 3.2 - January 2012
       url: 3_2_release_notes.html
       description: Release notes for Rails 3.2.
     -
-      name: 3.1 Release Notes
+      name: Version 3.1 - August 2011
       url: 3_1_release_notes.html
       description: Release notes for Rails 3.1.
     -
-      name: 3.0 Release Notes
+      name: Version 3.0 - August 2010
       url: 3_0_release_notes.html
       description: Release notes for Rails 3.0.
     -
-      name: 2.3 Release Notes
+      name: Version 2.3 - March 2009
       url: 2_3_release_notes.html
       description: Release notes for Rails 2.3.
     -
-      name: 2.2 Release Notes
+      name: Version 2.2 - November 2008
       url: 2_2_release_notes.html
       description: Release notes for Rails 2.2.
diff --git a/guides/source/i18n.md b/guides/source/i18n.md
index 7465726dca..c61b6ad214 100644
--- a/guides/source/i18n.md
+++ b/guides/source/i18n.md
@@ -664,6 +664,26 @@ I18n.t 'activerecord.errors.messages'
 # => {:inclusion=>"is not included in the list", :exclusion=> ... }
 ```
 
+If you want to perform interpolation on a bulk hash of translations, you need to pass `deep_interpolation: true` as a parameter. When you have the following dictionary:
+
+```yaml
+en:
+  welcome:
+    title: "Welcome!"
+    content: "Welcome to the %{app_name}"
+```
+
+then the nested interpolation will be ignored without the setting:
+
+```ruby
+I18n.t 'welcome', app_name: 'book store'
+# => {:title=>"Welcome!", :content=>"Welcome to the %{app_name}"}
+
+I18n.t 'welcome', deep_interpolation: true, app_name: 'book store'
+# => {:title=>"Welcome!", :content=>"Welcome to the book store"}
+```
+
+
 #### "Lazy" Lookup
 
 Rails implements a convenient way to look up the locale inside _views_. When you have the following dictionary: