Log Message:
Update to 4.4

Changelog:
On December 8, 2015, WordPress Version 4.4, named for jazz musician Clifford \ 
Brown, was released to the public. For more information on this enhancement and \ 
bug-fix release, read the WordPress Blog, and see the Changelog for 4.4.

For Version 4.4, the database version (db_version in wp_options) changed to \ 
35700, and the Trac revision was 35842.

Highlights

twenty-sixteen-white-desktop-1x.png

    New Default Theme - Twenty Sixteen
        Modern take on the classic blog design
        Flexible header and fun color schemes will make your content shine
        Mobile-first and responsive

The Finer Points
responsive-devices-desktop-1x.png

    Responsive images:

WordPress now takes a smarter approach to displaying appropriate image sizes on \ 
any device, ensuring a perfect fit every time. You don’t need to do \ 
anything to your theme, it just works.
wp embed preview.png

    Embed your WordPress content:

Now you can embed your posts on other sites, even other WordPress sites. Simply \ 
drop a post URL into the editor and see an instant embed preview, complete with \ 
the title, excerpt, and featured image if you’ve set one. We’ll even \ 
include your site icon and links for comments and sharing.
reverbnation embed.png

    Even more embed providers:

In addition to post embeds, WordPress 4.4 also adds support for five new oEmbed \ 
providers: Cloudup, Reddit Comments, ReverbNation, Speaker Deck, and VideoPress.
For Developers

    REST API infrastructure: Infrastructure for the REST API has been integrated \ 
into core, the first part of a multi-stage rollout. Inclusion of core endpoints \ 
is targeted for an upcoming release. To get a sneak peek of the core endpoints, \ 
and for more information on extending the REST API, check out the official \ 
WordPress REST API plugin.
    Term meta: Terms now support metadata, just like posts. See add_term_meta(), \ 
get_term_meta(), and update_term_meta() for more information.
    Comment query improvements: Comment queries now have cache handling to \ 
improve performance. New arguments in WP_Comment_Query make crafting robust \ 
comment queries simpler.
    Term, comment, and network objects: New WP_Term, WP_Comment, and WP_Network \ 
objects make interacting with terms, comments, and networks more predictable and \ 
intuitive in code.

What's New
General

    Developer reference - Improvements to inline code documentation.
    i18n support - Improvements to translation strings all over the core.
    Admin page headings were adjusted from H3 to H2 tags to reinforce page hierarchy
    Improvements to how list tables are displayed on all size screens

Posts

    The post/page permalink UI was simplified, linking the permalink and \ 
removing the "View" button

Media
Comments

    The "View Comment" link was relocated from the Status meta box in \ 
the comment-editing screen
    Many comment functions can now accept a full object instead of 'comment_ID' \ 
to reduce cache/db lookups
    Orphaned comments now fall back to the 'edit_posts' capability

Appearance

    Site icons will now fall back to the 'full' size URL when the 'thumbnail' \ 
size doesn't exist

Users
Install Process
Multisite

    The language chooser was added to the new site form on wp-signup.php
    Sites may no longer be created with the following reserved slugs: wp-admin, \ 
wp-content, wp-includes, or wp-json

Accessibility
Under The Hood
General

    Unclosed HTML elements in shortcode attributes were disallowed
    HTML was removed from all translatable text strings
    Rewrite rules are now flushed on theme switch
    Most core classes were moved to their own files

Embeds

    Add oEmbed support for Cloudup.
    Add oEmbed support for Reddit Comments.
    Add oEmbed support for ReverbNation.
    Add oEmbed support for Speaker Deck.
    Add oEmbed support for VideoPress.
    Remove oEmbed support for Blip.

JavaScript

    Customizer: Ensure persistence of unchanged active state for controls, \ 
sections, and panels
    Customizer: Fixed logic for determining the container element when focusing \ 
on a panel, section, or control
    Customizer: Fixed clearing of a color control's setting by using proper \ 
empty value

Bug Fixes

    Fail gracefully when checking mapped capabilities against unregistered post types
    Visibility was restored for the Tags auto-suggest tooltip in Quick Edit
    The $public_only parameter was added to count_user_posts()
    Cron: Events are now rejected when the provided $timestamp value is not a \ 
valid timestamp
    Users with no role are now redirected to the home page on login instead of \ 
their profile-editing screen

Multisite

    A network can now be retrieved by its ID through WP_Network::get_instance()
    A network can now be created or completed by passing arguments to WP_Network
    Network-level capabilities were clarified and some long-time bugs were fixed

Classes
What's New

    WP_Comment

    WP_Comment_Query->$found_comments
    WP_Comment_Query->$max_num_pages
    WP_Comment_Query->$meta_query_clauses
    WP_Comment_Query->$sql_clauses
    WP_Comment_Query::fill_descendants()
    WP_Comment_Query::get_comment_ids()

    WP_Customize_Manager->$autofocus
    WP_Customize_Manager->$preview_url
    WP_Customize_Manager->$return_url
    WP_Customize_Manager::customize_pane_settings()
    WP_Customize_Manager::get_autofocus()
    WP_Customize_Manager::get_document_title_template()
    WP_Customize_Manager::get_preview_url()
    WP_Customize_Manager::get_return_url()
    WP_Customize_Manager::is_ios()
    WP_Customize_Manager::set_autofocus()
    WP_Customize_Manager::set_preview_url()
    WP_Customize_Manager::set_return_url()

    WP_Customize_Setting->$is_multidimensional_aggregated
    WP_Customize_Setting->$is_previewed
    WP_Customize_Setting::$aggregated_multidimensionals
    WP_Customize_Setting::_multidimensional_preview_filter()
    WP_Customize_Setting::aggregate_multidimensional()
    get_root_value/ WP_Customize_Setting::get_root_value()
    id_data/ WP_Customize_Setting::id_data()
    set_root_value/ WP_Customize_Setting::set_root_value()

    WP_Customize_Widgets::get_widget_control_parts()
    WP_Customize_Widgets::is_panel_active()

    WP_Filesystem_SSH2::sftp_path()

    WP_HTTP_Response

    WP_List_Table::get_primary_column()

    WP_Locale->$start_of_week

    WP_MS_Sites_List_Table::column_id()

    WP_MS_Users_List_Table::column_id()

    WP_Media_List_Table->$comment_pending_count

    WP_Network

    WP_Posts_List_Table::get_edit_link()

    WP_Query->$is_embed
    WP_Query->$updated_comment_meta_cache
    WP_Query->$updated_term_meta_cache
    WP_Query::is_embed()
    WP_Query::lazyload_comment_meta()
    WP_Query::lazyload_term_meta()

    WP_REST_Request

    WP_REST_Response

    WP_REST_Server

    WP_Screen->$_screen_reader_content
    WP_Screen::get_screen_reader_content()
    WP_Screen::get_screen_reader_text()
    WP_Screen::remove_screen_reader_content()
    WP_Screen::render_list_table_columns_preferences()
    WP_Screen::render_meta_boxes_preferences()
    WP_Screen::render_screen_reader_content()
    WP_Screeb::render_view_mode()
    WP_Screen::set_screen_reader_content()

    WP_Term

    >$update WP_Theme

    WP_User::__unset()
    >$request WP_User_Query
    WP_User_Query::fill_query_vars()

    WP_Users_List_Table::get_role_list()

    WP_Widget_Calendar::$instance

    WP_Widget_Tag_Cloud::_get_current_taxonomy()

    WP_oEmbed_Controller

    wpdb->$termmeta

Deprecated
Functions
What's New

    _prime_comment_caches()
    add_network_option()
    add_term_meta()
    delete_network_option()
    delete_term_meta()
    enqueue_embed_scripts()
    get_header_image_tag()
    get_html_split_regex()
    get_network_option()
    get_oembed_endpoint_url()
    get_oembed_response_data()
    get_oembed_response_data_rich()
    get_password_reset_key()
    get_post_embed_html()
    get_post_embed_url()
    get_preview_post_link()
    get_rest_url()
    get_shortcode_atts_regex()
    get_subdirectory_reserved_names()
    get_term_meta()
    get_the_author_posts_link()
    get_the_comments_navigation()
    get_the_comments_pagination()
    get_the_post_thumbnail_url()
    is_embed()
    is_post_type_viewable()
    is_registered_sidebar()
    map_deep()
    print_embed_comments_button()
    print_embed_scripts()
    print_embed_sharing_button()
    print_embed_sharing_dialog()
    print_embed_styles()
    register_rest_route()
    rest_api_default_filters()
    rest_api_init()
    rest_api_loaded()
    rest_api_register_rewrites()
    rest_cookie_check_errors()
    rest_cookie_collect_status()
    rest_do_request()
    rest_ensure_request()
    rest_ensure_response()
    rest_get_date_with_gmt()
    rest_get_url_prefix()
    rest_handle_deprecated_argument()
    rest_handle_deprecated_function()
    rest_handle_options_request()
    rest_output_link_header()
    rest_output_link_wp_head()
    rest_output_rsd()
    rest_parse_date()
    rest_send_allow_header()
    rest_send_cors_headers()
    rest_url()
    signup_get_available_languages()
    strip_fragment_from_url()
    stripslashes_from_strings_only()
    the_comments_navigation()
    the_comments_pagination()
    the_excerpt_embed()
    the_header_image_tag()
    the_post_thumbnail_url()
    update_network_option()
    update_term_meta()
    update_termmeta_cache()
    urldecode_deep()
    wp_ajax_delete_inactive_widgets()
    wp_ajax_generate_password()
    wp_ajax_save_wporg_username()
    wp_calculate_image_sizes()
    wp_calculate_image_srcset()
    wp_embed_excerpt_attachment()
    wp_embed_excerpt_attachment()
    wp_filter_oembed_result()
    wp_get_attachment_image_sizes()
    wp_get_attachment_image_srcset()
    wp_get_attachment_image_url()
    wp_get_document_title()
    wp_get_server_protocol()
    wp_get_users_with_no_role()
    wp_handle_comment_submission()
    wp_image_add_srcset_and_sizes()
    wp_installing()
    wp_is_numeric_array()
    wp_make_content_images_responsive()
    wp_maybe_decline_date()
    wp_new_comment_notify_moderator()
    wp_new_comment_notify_postauthor()
    wp_oembed_add_discovery_links()
    wp_oembed_add_host_js()
    wp_oembed_ensure_format()
    wp_oembed_register_route()
    wp_parse_url()
    wp_remote_retrieve_cookie()
    wp_remote_retrieve_cookie_value()
    wp_remote_retrieve_cookies()
    wp_removable_query_args()
    wp_rest_server_class()
    wp_send_new_user_notifications()
    wp_term_is_shared()

Deprecated

    wp_get_http()

Actions & Filters
New Actions

    after_password_reset
    after_signup_site
    after_signup_user
    attachment_updated
    before_signup_header
    clean_user_cache
    customize_post_value_set
    customize_post_value_set_{$setting_id}
    delete_plugin
    delete_widget
    deleted_plugin
    edit_user_created_user
    embed_content
    embed_content_meta
    embed_footer
    embed_head
    enqueue_embed_scripts
    invite_user
    manage_posts_extra_tablenav
    ms_network_not_found
    network_site_new_created_user
    network_site_users_created_user
    network_user_new_created_user
    page_attributes_meta_box_template
    post_submitbox_minor_actions
    pre_auto_update
    register_new_user
    rest_api_init
    wp_add_nav_menu_item
    wp_mail_failed
    wp_verify_nonce_failed

New Filters

    admin_post_thumbnail_size
    comment_excerpt_length
    comment_form_fields
    content_pagination
    customize_loaded_components
    dashboard_recent_drafts_query_args
    dashboard_secondary_items
    default_hidden_columns
    document_title_parts
    document_title_separator
    duplicate_comment_id
    embed_html
    embed_oembed_discover
    embed_site_title_html
    embed_template
    embed_thumbnail_image_shape
    embed_thumbnail_image_size
    enclosure_links
    expiration_of_site_transient_{$transient}
    expiration_of_transient_{$transient}
    export_wp_filename
    feed_links_show_comments_feed
    feed_links_show_posts_feed
    found_comments_query
    get_header_image_tag
    get_page_of_comment
    get_page_uri
    get_post_status
    get_role_list
    get_sample_permalink
    get_terms_defaults
    get_{$adjacent}_post_excluded_terms
    hidden_columns
    illegal_user_logins
    image_get_intermediate_size
    insert_user_meta
    max_srcset_image_width
    mejs_settings
    nav_menu_item_args
    nav_menu_item_title
    navigation_markup_template
    network_admin_plugin_action_links
    network_admin_plugin_action_links_{$plugin_file}
    notify_moderator
    notify_post_author
    oembed_discovery_links
    oembed_endpoint_url
    oembed_min_max_width
    oembed_response_data
    old_slug_redirect_url
    plugin_action_links
    plugin_action_links_{$plugin_file}
    post_edit_category_parent_dropdown_args
    post_embed_url
    postmeta_form_keys
    pre_delete_post
    pre_get_document_title
    pre_get_lastpostmodified
    register_post_type_args
    register_taxonomy_args
    respond_link
    rest_url
    rest_url_prefix
    screen_options_show_submit
    show_network_active_plugins
    signup_get_available_languages
    subdirectory_reserved_names
    submenu_file
    taxonomy_labels_{$taxonomy}
    the_category_list
    the_excerpt_embed
    update_right_now_text
    user_profile_picture_description
    users_list_table_query_args
    view_mode_post_types
    wp_calculate_image_sizes
    wp_calculate_image_srcset
    wp_dropdown_users_args
    wp_http_ixr_client_headers
    wp_post_revision_title_expanded
    wp_prepare_revision_for_js
    wp_theme_editor_filetypes
    xmlrpc_chunk_parsing_size