WordPress 5.5 Field Guide

Update on 08 August 2020: Added “CoreCore Core is the set of software required to run WordPress. The Core Development Team builds WordPress. Editor AccessibilityAccessibility Accessibility (commonly shortened to a11y) refers to the design of products, devices, services, or environments for people with disabilities. The concept of accessible design ensures both “direct access” (i.e. unassisted) and “indirect access” meaning compatibility with a person’s assistive technology (for example, computer screen readers). (https://en.wikipedia.org/wiki/Accessibility) Improvements” and “New editor preview options”

Update on 06 August 2020: Added the “Registering default values for metaMeta Meta is a term that refers to the inside workings of a group. For us, this is the team that works on internal WordPress sites like WordCamp Central and Make WordPress. data” section.

WordPress 5.5 is shaping up to be “the best version of WordPress ever“!

As a user, you’ll see automatic updates for plugins and themes, a blockBlock Block is the abstract term used to describe units of markup that, composed together, form the content or layout of a webpage using the WordPress editor. The idea combines concepts of what in the past may have achieved with shortcodes, custom HTML, and embed discovery into a single consistent API and user experience. directory, XML sitemaps, lazy-loading images, and the latest and greatest featured in the block editor. As a developer, you’ll see 157 enhancements and feature requests, 307 bug fixes, and more! Of course, all those improvements mean code changes, which could in turn require you to make updates to your site, pluginPlugin A plugin is a piece of software containing a group of functions that can be added to a WordPress website. They can extend functionality or add new features to your WordPress websites. WordPress plugins are written in the PHP programming language and integrate seamlessly with WordPress. These can be free in the WordPress.org Plugin Directory https://wordpress.org/plugins/ or can be cost-based plugin from a third-party, or theme.

So take a look through this Field GuideField guide The field guide is a type of blogpost published on Make/Core during the release candidate phase of the WordPress release cycle. The field guide generally lists all the dev notes published during the beta cycle. This guide is linked in the about page of the corresponding version of WordPress, in the release post and in the HelpHub version page., and see what’s relevant to you and your users, among the many improvements coming in 5.5…


Of the 34 various accessibility updates, Theme developers are highly encouraged to utilize the opt-in navigation-widgets feature to improve the semantics and accessibility of widgets with lists of links in themes. When support is declared, all default widgets included in WordPress Core that produce lists of links will be output wrapped in the <nav> element and an aria-label attribute is automatically generated based on the widgetWidget A WordPress Widget is a small block that performs a specific function. You can add these widgets in sidebars also known as widget-ready areas on your web page. WordPress widgets were originally created to provide a simple and easy-to-use way of giving design and structure control of the WordPress theme to the user.’s title field and added to the nav element. Read the following dev notedev note Each important change in WordPress Core is documented in a developers note, (usually called dev note). Good dev notes generally include a description of the change, the decision that led to this change, and a description of how developers are supposed to work with that change. Dev notes are published on Make/Core blog during the beta phase of WordPress release cycle. Publishing dev notes is particularly important when plugin/theme authors and WordPress developers need to be aware of those changes.In general, all dev notes are compiled into a Field Guide at the beginning of the release candidate phase. to learn which widgets are affected, how to declare support, and other details behind this update.

Auto-updates (Security)

On the 6 security updates, the new core-auto-updates team worked on introducing a new UIUI User interface to manage Plugins and Themes automatic updates. Learn more about controlling this new UI, email notifications, site health screen, and if you’re a plugin developer, ensure your plugin is ready for the new auto-updates system.


Of the seven updates to the Customize component, Theme developers will want to take notice of changes to how the custom logo is linked on the homepage and a new logo image attributes filterFilter Filters are one of the two types of Hooks https://codex.wordpress.org/Plugin_API/Hooks. They provide a way for functions to modify data of other functions. They are the counterpart to Actions. Unlike Actions, filters are meant to work in an isolated manner, and should never have side effects such as affecting global variables and output..

Block Editor

The block editor has continued its rapid iteration since WordPress 5.0. Now it has GutenbergGutenberg The Gutenberg project is the new Editor Interface for WordPress. The editor improves the process and experience of creating new content, making writing rich content much simpler. It uses ‘blocks’ to add richness rather than shortcodes, custom HTML etc. https://wordpress.org/gutenberg/ version 8.5 bundled with WordPress 5.5; that’s ten releases all bundled into this release (versions 7.6, 7.7, 7.8, 7.9, 8.0, 8.1, 8.2, 8.3, 8.4, and 8.5)! Bug fixes and performance improvements from Gutenberg versions 8.6 and 8.7 will also be part of 5.5.

The WordPress 5.5 Beta 1 post highlights a lot of new features and improvements across these releases, though you’ll also want to note inline image editing, block patterns, device previews, block directory, among many other improvements bringing forth a better, smoother editing experience.

Below you’ll find details on updates to various Block APIs, how to register a block pattern, how themes can opt-out from core bundled block patterns, image editing via the REST APIREST API The REST API is an acronym for the RESTful Application Program Interface (API) that uses HTTP requests to GET, PUT, POST and DELETE data. It is how the front end of an application (think “phone app” or “website”) can communicate with the data store (think “database” or “file system”) https://developer.wordpress.org/rest-api/. and how edited images are saved as a new attachment, custom line heights and custom units as new block tools, changes to the BlockPreview, URLInput, and Popover ReactReact React is a JavaScript library that makes it easy to reason about, construct, and maintain stateless and stateful user interfaces. https://reactjs.org/. components, and how to add your block plugin directly to the Block Directory.


There are 26 updates to the Media component, including the core merge of the Lazy Loading featured plugin that now sees images lazy-loaded by default. Read on to learn more about reduced layout shifting as a prerequisite, how to customize lazy-loading, and browser compatibility.


36 updates to the REST API with particular interest pointed to new and modified endpoints, parameter and JSONJSON JSON, or JavaScript Object Notation, is a minimal, readable format for structuring data. It is used primarily to transmit data between a server and web application, as an alternative to XML. schema changes, discoverable REST resource links, new APIAPI An API or Application Programming Interface is a software intermediary that allows programs to interact with each other and share data in limited, clearly defined ways. functions, CORS changes, the new register_theme_feature() function and its arguments, and other miscellaneous updates.

Options, Meta APIs


The new Sitemaps component and its 13 items in WordPress 5.5 comes from the XML sitemaps feature project merge. Read on to learn more about adding custom sitemaps, removing certain sitemaps, adding additional tags to sitemap entries, excluding a single post from the sitemap, completely disabling sitemaps functionality, and the new classes, functions, hooksHooks In WordPress theme and development, hooks are functions that can be applied to an action or a Filter in WordPress. Actions are functions performed when a certain event occurs in WordPress. Filters allow you to modify certain functions. Arguments used to hook both filters and actions look the same., and filters.


This release sees the introduction of a Theme Field Guide! You’ll find a few theme related changes that were not large enough for their own developer note included here, as well as links to the other dev notesdev note Each important change in WordPress Core is documented in a developers note, (usually called dev note). Good dev notes generally include a description of the change, the decision that led to this change, and a description of how developers are supposed to work with that change. Dev notes are published on Make/Core blog during the beta phase of WordPress release cycle. Publishing dev notes is particularly important when plugin/theme authors and WordPress developers need to be aware of those changes.In general, all dev notes are compiled into a Field Guide at the beginning of the release candidate phase. above that are theme related.

Other Developer Updates

There are even more goodies in 5.5! Here are a few:

  • Update a plugin or theme by uploading a ZIP file
  • Default categories for custom post types
  • Support for default terms in custom taxonomies
  • Enforcing a default comment_type value
  • Updates to the PHPMailer, SimplePie, Twemoji, Masonry, imagesLoaded, getID3, Moment.js, and clipboard.js external libraries
  • Template loading functions now allow additional arguments to be passed through to the matched template file using a new $args parameter
  • WordPress now attempts to invalidate PHPPHP The web scripting language in which WordPress is primarily architected. WordPress requires PHP 5.6.20 or higher files when Core, Plugins, or Themes are updated via wp_opcache_invalidate()
  • How theme authors can filter archive page headings
  • The new createInterpolateElement and wp_get_environment_type() functions
  • Better control of the redirect_guess_404_permalink() function
  • New CSSCSS Cascading Style Sheets. styles for buttons with disabled state
  • The final update to the Dashicons icon font as focus now shifts to the new Icon component
  • Various PHP-related improvements and changes
  • So much much more!

Read through the dev notes below to see details on all these changes coming in 5.5.

But Wait, There is More!

Over 307 bugs, 157 enhancements and feature requests, and 31 blessed tasks have been marked as fixed in WordPress 5.5. Some additional ones to highlight include:

  • Comments: The proper comment counts and page numbers for unapproved comments are now calculated correctly. (#8973)
  • Comments: get_comment_count() now returns integers for all counts of all statuses returned (#48093)
  • Customize: The CustomizerCustomizer Tool built into WordPress core that hooks into most modern themes. You can use it to preview and modify many of your site’s appearance settings. UI is now themed correctly based on the selected adminadmin (and super admin) theme (#50547)
  • Internationalization: Domain-specific i18Ni18n Internationalization, or the act of writing and preparing code to be fully translatable into other languages. Also see localization. Often written with a lowercase i so it is not confused with a lowercase L or the numeral 1. Often an acquired skill. filter hooks have been added. (#49518)
  • Media: sanitize_file_name() now correctly sanitizes filenames, removing accents (#22363)
  • Menus: Menu Settings are now provided when creating a new menu (#44286)
  • Menus: Empty taxonomyTaxonomy A taxonomy is a way to group things together. In WordPress, some common taxonomies are category, link, tag, or post format. https://codex.wordpress.org/Taxonomies#Default_Taxonomies. terms now show up in searches when adding items to menus (#45298)
  • Widgets: Widgets with custom image sizes now correctly display captions (#50160)

Please, test your code. Fixing issues helps you and helps millions of WordPress sites.

Props to @jeffpaul, @audrasjb, @desrosj for contributing to this guide.

#5-5, #field-guide