[ci skip] Add changelog entries for PR #3828
diff --git a/application/config/config.php b/application/config/config.php
index 86ca312..f4ba70a 100644
--- a/application/config/config.php
+++ b/application/config/config.php
@@ -284,8 +284,15 @@
 | Cache Include Query String
 |--------------------------------------------------------------------------
 |
-| Set this to TRUE if you want to use different cache files depending on the
-| URL query string.  Please be aware this might result in numerous cache files.
+| Whether to take the URL query string into consideration when generating
+| output cache files. Valid options are:
+|
+|	FALSE      = Disabled
+|	TRUE       = Enabled, take all query parameters into account.
+|	             Please be aware that this may result in numerous cache
+|	             files generated for the same page over and over again.
+|	array('q') = Enabled, but only take into account the specified list
+|	             of query parameters.
 |
 */
 $config['cache_query_string'] = FALSE;
diff --git a/user_guide_src/source/changelog.rst b/user_guide_src/source/changelog.rst
index 3a18048..d175f4b 100644
--- a/user_guide_src/source/changelog.rst
+++ b/user_guide_src/source/changelog.rst
@@ -30,6 +30,10 @@
    -  Added Unicode support to :doc:`URL Helper <helpers/url_helper>` function :php:func:`url_title()`.
    -  Added support for passing the "extra" parameter as an array to all :doc:`Form Helper <helpers/form_helper>` functions that use it.
 
+-  Core
+
+   -  Added support for defining a list of specific query parameters in ``$config['cache_query_string']`` for the :doc:`Output Library <libraries/output>`.
+
 Bug fixes for 3.0.1
 -------------------
 
@@ -58,6 +62,7 @@
 -  Fixed a bug (#3965) - :doc:`File Uploading Library <libraries/file_uploading>` ignored the "encrypt_name" setting when "overwrite" is enabled.
 -  Fixed a bug (#3968) - :doc:`Database Forge <database/forge>` method ``add_key()`` didn't treat array inputs as composite keys unless it's a PRIMARY KEY.
 -  Fixed a bug (#3715) - :doc:`Pagination Library <libraries/pagination>` could generate broken link when a protocol-relative base URL is used.
+-  Fixed a bug (#3828) - :doc:`Output Library <libraries/output>` method ``delete_cache()`` couldn't delete index page caches.
 
 Version 3.0.0
 =============