6 files changed, 39 insertions, 25 deletions
diff --git a/guides/source/5_0_release_notes.md b/guides/source/5_0_release_notes.md
index a868c5f856..3b926c04f0 100644
--- a/guides/source/5_0_release_notes.md
+++ b/guides/source/5_0_release_notes.md
@@ -270,7 +270,7 @@ Please refer to the [Changelog][action-pack] for detailed changes.
 *   Changed the `protect_from_forgery` prepend default to `false`.
     ([commit](https://github.com/rails/rails/commit/39794037817703575c35a75f1961b01b83791191))
 
-*   `ActionController::TestCase` will be moved to it's own gem in Rails 5.1. Use
+*   `ActionController::TestCase` will be moved to its own gem in Rails 5.1. Use
     `ActionDispatch::IntegrationTest` instead.
     ([commit](https://github.com/rails/rails/commit/4414c5d1795e815b102571425974a8b1d46d932d))
 
@@ -322,10 +322,6 @@ Please refer to the [Changelog][action-view] for detailed changes.
     ([Pull Request](https://github.com/rails/rails/pull/18948),
     [commit](https://github.com/rails/rails/commit/e93f0f0f133717f9b06b1eaefd3442bd0ff43985))
 
-*   Allow defining explicit collection caching using a `# Template Collection: ...`
-    directive inside templates.
-    ([Pull Request](https://github.com/rails/rails/pull/20781))
-
 *   Added wildcard matching to explicit dependencies.
     ([Pull Request](https://github.com/rails/rails/pull/20904))
 
@@ -355,9 +351,6 @@ Please refer to the [Changelog][action-mailer] for detailed changes.
 *   Template lookup now respects default locale and I18n fallbacks.
     ([commit](https://github.com/rails/rails/commit/ecb1981b))
 
-*   Template can use fragment cache like Action View template.
-    ([Pull Request](https://github.com/rails/rails/pull/22825))
-
 *   Added `_mailer` suffix to mailers created via generator, following the same
     naming convention used in controllers and jobs.
     ([Pull Request](https://github.com/rails/rails/pull/18074))
@@ -509,9 +502,6 @@ Please refer to the [Changelog][active-record] for detailed changes.
 *   Added `#cache_key` to `ActiveRecord::Relation`.
     ([Pull Request](https://github.com/rails/rails/pull/20884))
 
-*   Added `ActiveRecord::Relation#outer_joins`.
-    ([Pull Request](https://github.com/rails/rails/pull/12071))
-
 *   Require `belongs_to` by default.
     ([Pull Request](https://github.com/rails/rails/pull/18937)) - Deprecate
     `required` option in favor of `optional` for `belongs_to`
diff --git a/guides/source/action_view_overview.md b/guides/source/action_view_overview.md
index 46116b1e47..0e6bb76101 100644
--- a/guides/source/action_view_overview.md
+++ b/guides/source/action_view_overview.md
@@ -177,7 +177,7 @@ would produce:
 }
 ```
 
-See the [Jbuilder documention](https://github.com/rails/jbuilder#jbuilder) for
+See the [Jbuilder documentation](https://github.com/rails/jbuilder#jbuilder) for
 more examples and information.
 
 #### Template Caching
@@ -1419,7 +1419,7 @@ number_to_percentage(100, precision: 0)        # => 100%
 
 #### number_to_phone
 
-Formats a number into a US phone number.
+Formats a number into a phone number (US by default).
 
 ```ruby
 number_to_phone(1235551234) # => 123-555-1234
diff --git a/guides/source/active_model_basics.md b/guides/source/active_model_basics.md
index a8199e5d02..e834aeadb1 100644
--- a/guides/source/active_model_basics.md
+++ b/guides/source/active_model_basics.md
@@ -13,7 +13,7 @@ After reading this guide, you will know:
 * How an Active Record model behaves.
 * How Callbacks and validations work.
 * How serializers work.
-* The Rails internationalization (i18n) framework.
+* How Active Model integrates with the Rails internationalization (i18n) framework.
 
 --------------------------------------------------------------------------------
 
diff --git a/guides/source/active_record_validations.md b/guides/source/active_record_validations.md
index baaebd21c8..1cf4abce10 100644
--- a/guides/source/active_record_validations.md
+++ b/guides/source/active_record_validations.md
@@ -785,7 +785,7 @@ A `String` `:message` value can optionally contain any/all of `%{value}`,
 `%{attribute}`, and `%{model}` which will be dynamically replaced when
 validation fails.
 
-A `Proc` `:message` value is given two arguments: a message key for i18n, and
+A `Proc` `:message` value is given two arguments: the object being validated, and
 a hash with `:model`, `:attribute`, and `:value` key-value pairs.
 
 ```ruby
@@ -801,10 +801,10 @@ class Person < ApplicationRecord
   # Proc
   validates :username,
     uniqueness: {
-      # key = "activerecord.errors.models.person.attributes.username.taken"
+      # object = person object being validated
       # data = { model: "Person", attribute: "Username", value: <username> }
-      message: ->(key, data) do
-        "#{data[:value]} taken! Try again #{Time.zone.tomorrow}"
+      message: ->(object, data) do
+        "Hey #{object.name}!, #{data[:value]} is taken already! Try again #{Time.zone.tomorrow}"
       end
     }
 end
@@ -1217,9 +1217,9 @@ person.errors[:name]
 person.errors.clear
 person.errors.empty? # => true
 
-p.save # => false
+person.save # => false
 
-p.errors[:name]
+person.errors[:name]
 # => ["can't be blank", "is too short (minimum is 3 characters)"]
 ```
 
diff --git a/guides/source/caching_with_rails.md b/guides/source/caching_with_rails.md
index ebd67a4adb..ae204a55d6 100644
--- a/guides/source/caching_with_rails.md
+++ b/guides/source/caching_with_rails.md
@@ -512,12 +512,38 @@ class ProductsController < ApplicationController
 end
 ```
 
-### A note on weak ETags
+### Strong v/s Weak ETags
 
-Etags generated by Rails are weak by default. Weak etags allow symantically equivalent responses to have the same etags, even if their bodies do not match exactly. This is useful when we don't want the page to be regenerated for minor changes in response body. If you absolutely need to generate a strong etag, it can be assigned to the header directly.
+Rails generates weak ETags by default. Weak ETags allow semantically equivalent
+responses to have the same ETags, even if their bodies do not match exactly.
+This is useful when we don't want the page to be regenerated for minor changes in
+response body.
+
+Weak ETags have a leading `W/` to differentiate them from strong ETags.
+
+```
+  W/"618bbc92e2d35ea1945008b42799b0e7" → Weak ETag
+  "618bbc92e2d35ea1945008b42799b0e7" → Strong ETag
+```
+
+Unlike weak ETag, Strong ETag implies that response should be exactly same
+and byte by byte identical. Useful when doing Range requests within a
+large video or PDF file. Some CDNs support only strong ETags, like Akamai.
+If you absolutely need to generate a strong ETag, it can be done as follows.
+
+```ruby
+  class ProductsController < ApplicationController
+    def show
+      @product = Product.find(params[:id])
+      fresh_when last_modified: @product.published_at.utc, strong_etag: @product
+    end
+  end
+```
+
+You can also set the strong ETag directly on the response.
 
 ```ruby
-  response.add_header "ETag", Digest::MD5.hexdigest(response.body)
+  response.strong_etag = response.body # => "618bbc92e2d35ea1945008b42799b0e7"
 ```
 
 References
diff --git a/guides/source/form_helpers.md b/guides/source/form_helpers.md
index 422bc647ef..048fe190e8 100644
--- a/guides/source/form_helpers.md
+++ b/guides/source/form_helpers.md
@@ -174,7 +174,6 @@ URL fields, email fields, number fields and range fields:
 <%= search_field(:user, :name) %>
 <%= telephone_field(:user, :phone) %>
 <%= date_field(:user, :born_on) %>
-<%= datetime_field(:user, :meeting_time) %>
 <%= datetime_local_field(:user, :graduation_day) %>
 <%= month_field(:user, :birthday_month) %>
 <%= week_field(:user, :birthday_week) %>
@@ -195,7 +194,6 @@ Output:
 <input id="user_name" name="user[name]" type="search" />
 <input id="user_phone" name="user[phone]" type="tel" />
 <input id="user_born_on" name="user[born_on]" type="date" />
-<input id="user_meeting_time" name="user[meeting_time]" type="datetime" />
 <input id="user_graduation_day" name="user[graduation_day]" type="datetime-local" />
 <input id="user_birthday_month" name="user[birthday_month]" type="month" />
 <input id="user_birthday_week" name="user[birthday_week]" type="week" />