4 files changed, 29 insertions, 3 deletions
diff --git a/guides/source/4_2_release_notes.md b/guides/source/4_2_release_notes.md
index 73e6c2c05b..a30bfc458a 100644
--- a/guides/source/4_2_release_notes.md
+++ b/guides/source/4_2_release_notes.md
@@ -871,7 +871,7 @@ Please refer to the [Changelog][active-support] for detailed changes.
     `module Foo; extend ActiveSupport::Concern; end` boilerplate.
     ([Commit](https://github.com/rails/rails/commit/b16c36e688970df2f96f793a759365b248b582ad))
 
-*   New [guide](constant_autoloading_and_reloading.html) about constant autoloading and reloading.
+*   New [guide](autoloading_and_reloading_constants.html) about constant autoloading and reloading.
 
 Credits
 -------
diff --git a/guides/source/5_0_release_notes.md b/guides/source/5_0_release_notes.md
index 638547565c..a07ce7e859 100644
--- a/guides/source/5_0_release_notes.md
+++ b/guides/source/5_0_release_notes.md
@@ -50,7 +50,7 @@ ToDo...
 
 Defines an attribute with a type on a model. It will override the type of existing attributes if needed. 
 This allows control over how values are converted to and from SQL when assigned to a model.
-It also changes the behavior of values passed to ActiveRecord::Base.where, which lets use our domain objects across much of Active Record, 
+It also changes the behavior of values passed to `ActiveRecord::Base.where`, which lets use our domain objects across much of Active Record,
 without having to rely on implementation details or monkey patching.
 
 Some things that you can achieve with this:
diff --git a/guides/source/configuring.md b/guides/source/configuring.md
index 51a2649ec0..47b0fd1404 100644
--- a/guides/source/configuring.md
+++ b/guides/source/configuring.md
@@ -242,6 +242,12 @@ This will put the `Magical::Unicorns` middleware on the end of the stack. You ca
 config.middleware.insert_before Rack::Head, Magical::Unicorns
 ```
 
+Or you can insert a middleware to exact position by using indexes. For example, if you want to insert `Magical::Unicorns` middleware on top of the stack, you can do it, like so:
+
+```ruby
+config.middleware.insert_before 0, Magical::Unicorns
+```
+
 There's also `insert_after` which will insert a middleware after another:
 
 ```ruby
@@ -272,6 +278,26 @@ All these configuration options are delegated to the `I18n` library.
 
 * `config.i18n.load_path` sets the path Rails uses to look for locale files. Defaults to `config/locales/*.{yml,rb}`.
 
+* `config.i18n.fallbacks` sets fallback behavior for missing translations. Here are 3 usage examples for this option:
+
+  * You can set the option to `true` for using default locale as fallback, like so:
+
+    ```ruby
+    config.i18n.fallbacks = true
+    ```
+
+  * Or you can set an array of locales as fallback, like so:
+
+    ```ruby
+    config.i18n.fallbacks = [:tr, :en]
+    ```
+
+  * Or you can set different fallbacks for locales individually. For example, if you want to use `:tr` for `:az` and `:de`, `:en` for `:da` as fallbacks, you can do it, like so:
+
+    ```ruby
+    config.i18n.fallbacks = { az: :tr, da: [:de, :en] }
+    ```
+
 ### Configuring Active Record
 
 `config.active_record` includes a variety of configuration options:
diff --git a/guides/source/layout.html.erb b/guides/source/layout.html.erb
index 6db76b528e..9abb863da6 100644
--- a/guides/source/layout.html.erb
+++ b/guides/source/layout.html.erb
@@ -111,7 +111,7 @@
           <%= link_to 'open an issue', 'https://github.com/rails/rails/issues' %>.
         </p>
         <p>And last but not least, any kind of discussion regarding Ruby on Rails
-          documentation is very welcome in the <%= link_to 'rubyonrails-docs mailing list', 'http://groups.google.com/group/rubyonrails-docs' %>.
+          documentation is very welcome in the <%= link_to 'rubyonrails-docs mailing list', 'https://groups.google.com/forum/#!forum/rubyonrails-docs' %>.
         </p>
       </div>
     </div>