This files describes API changes in core libraries and APIs,
information provided here is intended especially for developers.
=== 2.5.2 ===
* Use new function moodleform::mock_submit() to simulate form submission in unit tests.
* Use behat_selectors::get_allowed_text_selectors() and behat_selectors::get_allowed_selectors() instead of
  behat_command::$allowedtextselectors and behat_command::$allowedselectors

=== 2.5.1 ===

* New get_course() function for use when obtaining the course record from database. Will
  reuse existing $COURSE or $SITE globals if possible to improve performance.

=== 2.5 ===

* The database drivers (moodle_database and subclasses) aren't using anymore the ::columns property
  for caching database metadata. MUC (databasemeta) is used instead. Any custom DB driver should
  apply for that change.
* The cron output has been changed to include time and memory usage (see cron_trace_time_and_memory()),
  so any custom utility relying on the old output may require modification.
* Function get_max_file_sizes now returns an option for (for example) "Course limit (500MB)" or
  "Site limit (200MB)" when appropriate with the option set to 0. This function no longer returns
  an option for 0 bytes. Existing code that was replacing the 0 option in the return
  from this function with a more sensible message, can now use the return from this function directly.
* Functions responsible for output in course/lib.php are deprecated, the code is moved to
  appropriate renderers: print_section(), print_section_add_menus(), get_print_section_cm_text(),
  make_editing_buttons()
  See functions' phpdocs in lib/deprecatedlib.php
* Function get_print_section_cm_text() is deprecated, replaced with methods in cm_info
* zip_packer may create empty zip archives, there is a new option to ignore
  problematic files when creating archive
* The function delete_course_module was deprecated and has been replaced with
  course_delete_module. The reason for this was because the function delete_course_module
  only partially deletes data, so wherever it was called extra code was needed to
  perform the whole deletion process. The function course_delete_module now takes care
  of the whole process.
* curl::setopt() does not accept constant values any more. As it never worked properly,
  we decided to make the type check stricter. Now, the keys of the array pass must be a string
  corresponding to the curl constant name.
* Function get_users_listing now return list of users except guest and deleted users. Previously
  deleted users were excluded by get_users_listing. As guest user is not expected while browsing users,
  and not included in get_user function, it will not be returned by get_users_listing.
* The add_* functions in course/dnduploadlib.php have been deprecated. Plugins should be using the
  MODNAME_dndupload_register callback instead.
* The signature of the add() method of classes implementing the parentable_part_of_admin_tree
  interface (such as admin_category) has been extended. The new parameter allows the caller
  to prepend the new node before an existing sibling in the admin tree.
* condition_info:get_condition_user_fields($formatoptions) now accepts the optional
  param $formatoptions, that will determine if the field names are processed by
  format_string() with the passed options.
* remove all references to $CFG->gdversion, GD PHP extension is now required
* Formslib will now throw a developer warning if a PARAM_ type hasn't been set for elements which
  need it. Please set PARAM_RAW explicitly if you do not want any cleaning.
* Functions responsible for managing and accessing course categories are moved to class coursecat
  in lib/coursecatlib.php, functions responsible for rendering courses and categories lists are
  moved to course/renderer.php. The following global functions are deprecated: make_categories_list(),
  category_delete_move(), category_delete_full(), move_category(), course_category_hide(),
  course_category_show(), get_course_category(), create_course_category(), get_all_subcategories(),
  get_child_categories(), get_categories(), print_my_moodle(), print_remote_course(),
  print_remote_host(), print_whole_category_list(), print_category_info(), get_course_category_tree(),
  print_courses(), print_course(), get_category_courses_array(), get_category_courses_array_recursively(),
  get_courses_wmanagers()
  See http://docs.moodle.org/dev/Courses_lists_upgrade_to_2.5
* $core_renderer->block_move_target() changed to support more verbose move-block-here descriptions.
* Additional (optional) param $onlyactive has been added to get_enrolled_users, count_enrolled_users
  functions to get information for only active (excluding suspended enrolments) users. Included two
  helper functions extract_suspended_users, get_suspended_userids to extract suspended user information.
* The plugin_manager class now provides two new helper methods for getting information
  about known plugins: get_plugins_of_type() and get_subplugins_of_plugin().
* The get_uninstall_url() method of all subclasses of plugininfo_base class is now expected
  to always return moodle_url. Subclasses can use the new method is_uninstall_allowed()
  to control the availability of the 'Uninstall' link at the Plugins overview page (previously
  they would do it by get_uninstall_url() returning null). By default, URL to a new general plugin
  uninstall tool is returned. Unless the plugin type needs extra steps that can't be handled by
  plugininfo_xxx::uninstall() method or xmldb_xxx_uninstall() function, this default URL should
  satisfy all plugin types.

Database (DML) layer:
* $DB->sql_empty() is deprecated, you have to use sql parameters with empty values instead,
  please note hardcoding of empty strings in SQL queries breaks execution in Oracle database.
* Indexes must not be defined on the same columns as keys, this is now reported as fatal problem.
  Please note that internally we create indexes instead of foreign keys.

YUI changes:
* M.util.help_icon has been deprecated. Code should be updated to use moodle-core-popuphelp
  instead. To do so, remove any existing JS calls to M.util.help_icon from your PHP and ensure
  that your help link is placed in a span which has the class 'helplink'.

=== 2.4 ===

* Pagelib: Numerous deprecated functions were removed as classes page_base, page_course
  and page_generic_activity.
* use $CFG->googlemapkey3 instead of removed $CFG->googlemapkey and migrate to Google Maps API V3
* Function settings_navigation::add_course_editing_links() is completely removed
* function global_navigation::format_display_course_content() is removed completely (the
  functionality is moved to course format class)
* in the function global_navigation::load_generic_course_sections() the argument $courseformat is
  removed
* New component and itemid columns in groups_members table - this allows plugin to create protected
  group memberships using 'xx_yy_allow_group_member_remove' callback and there is also a new restore
  callback 'xx_yy_restore_group_member()'.
* New general role assignment restore plugin callback 'xx_yy_restore_role_assignment()'.
* functions get_generic_section_name(), get_all_sections(), add_mod_to_section(), get_all_mods()
  are deprecated. See their phpdocs in lib/deprecatedlib.php on how to replace them

YUI changes:
* moodle-enrol-notification has been renamed to moodle-core-notification
* YUI2 code must now use 2in3, see http://yuilibrary.com/yui/docs/yui/yui-yui2.html
* M.util.init_select_autosubmit() and M.util.init_url_select() have been deprecated. Code using this should be updated
  to use moodle-core-formautosubmit

Unit testing changes:
* output debugging() is not sent to standard output any more,
  use $this->assertDebuggingCalled(), $this->assertDebuggingNotCalled(),
  $this->getDebuggingMessages() or $this->assertResetDebugging() instead.

=== 2.3 ===

Database layer changes:
* objects are not allowed in paramters of DML functions, use explicit casting to strings if necessary

Note:
* DDL and DML methods which were deprecated in 2.0 have now been removed, they will no longer produce
debug messages and will produce fatal errors

API changes:

* send_stored_file() has changed its interface
* deleted several resourcelib_embed_* functions from resourcelib.php

=== 2.2 ===

removed unused libraries:
* odbc, base32, CodeSniffer, overlib, apd profiling, kses, Smarty, PEAR Console, swfobject, cssshover.htc, md5.js

API changes:
* new admin/tool plugin type
* new context API - old API is still available
* deleted users do not have context any more
* removed global search


=== 2.1 ===

API changes:
* basic suport for restore from 1.9
* new mobile devices API
* new questions API


=== 2.0 ===

API changes:
* new DML API - http://docs.moodle.org/dev/DML_functions
* new DDL API - http://docs.moodle.org/dev/DDL_functions
* new file API - http://docs.moodle.org/dev/File_API
* new $PAGE and $OUTPUT API
* new navigation API
* new theme API - http://docs.moodle.org/dev/Theme_changes_in_2.0
* new javascript API - http://docs.moodle.org/dev/JavaScript_usage_guide
* new portfolio API
* new local plugin type
* new translation support - http://lang.moodle.org
* new web service API
* new cohorts API
* new messaging API
* new rating API
* new comment API
* new sessions API
* new enrolment API
* new backup/restore API
* new blocks API
* new filters API
* improved plugin support (aka Frankenstyle)
* new registration and hub API
* new course completion API
* new plagiarism API
* changed blog API
* new text editor API
* new my moodle and profiles API
