diff --git a/config/locales/client.en.yml b/config/locales/client.en.yml
index 71a635f9a..186c46288 100644
--- a/config/locales/client.en.yml
+++ b/config/locales/client.en.yml
@@ -153,7 +153,6 @@ en:
     sign_up: "Sign Up"
     log_in: "Log In"
     age: "Age"
-    last_post: "Last Post"
     joined: "Joined"
     admin_title: "Admin"
     flags_title: "Flags"
diff --git a/config/locales/server.en.yml b/config/locales/server.en.yml
index 1a91ce928..2cab867e2 100644
--- a/config/locales/server.en.yml
+++ b/config/locales/server.en.yml
@@ -20,17 +20,21 @@ en:
     short_date: "D MMM, YYYY"
     long_date: "MMMM D, YYYY h:mma"
 
-  datetime: &datetime
-    month_names:
-      [~, January, February, March, April, May, June, July, August, September, October, November, December]
+  datetime_formats: &datetime_formats
     formats:
+      # Format directives: http://ruby-doc.org/core-2.2.0/Time.html#method-i-strftime
       short: "%m-%d-%Y"
+      # Format directives: http://ruby-doc.org/core-2.2.0/Time.html#method-i-strftime
       short_no_year: "%B %-d"
+      # Format directives: http://ruby-doc.org/core-2.2.0/Time.html#method-i-strftime
       date_only: "%B %-d, %Y"
   date:
-    <<: *datetime
+    # Do not remove the brackets and commas and do not translate the first month name. It should be "null".
+    month_names:
+      [~, January, February, March, April, May, June, July, August, September, October, November, December]
+    <<: *datetime_formats
   time:
-    <<: *datetime
+    <<: *datetime_formats
 
   title: "Discourse"
   topics: "Topics"
@@ -62,8 +66,10 @@ en:
       exclusion: is reserved
       greater_than: must be greater than %{count}
       greater_than_or_equal_to: must be greater than or equal to %{count}
+      has_already_been_used: "has already been used"
       inclusion: is not included in the list
       invalid: is invalid
+      is_invalid: "is invalid; try to be a little more descriptive"
       less_than: must be less than %{count}
       less_than_or_equal_to: must be less than or equal to %{count}
       not_a_number: is not a number
@@ -101,9 +107,6 @@ en:
   activemodel:
     errors:
       <<: *errors
-  activerecord:
-    errors:
-      <<: *errors
 
   bulk_invite:
     file_should_be_csv: "The uploaded file should be of csv or txt format."
@@ -280,9 +283,7 @@ en:
       user:
         ip_address: ""
     errors:
-      messages:
-        is_invalid: "is invalid; try to be a little more descriptive"
-        has_already_been_used: "has already been used"
+      <<: *errors
       models:
         topic:
           attributes: