WordPress 5.3 Field Guide

Update on 18 October 2019: Added the “Noteworthy Admin CSS changes in WordPress 5.3” dev note to the Accessibility section

WordPress 5.3 is shaping up to be the best WordPress yet! Users will see new blocks, more intuitive block editor interactions, improved media handling, improved accessibility, and the new Twenty Twenty default theme. Among many goodies in 5.3, developers will love the date/time component improvements, PHP 7.4 compatibility, and will also be able to take advantage of 157 enhancements and feature requests, 366 bug fixes, and more! Let’s look at the many improvements coming in 5.3…


Of the 50 updates related to Accessibility in 5.3, you’ll want to particularly note the changes to Admin CSS, improvements of all the media views form controls and changes to explicit labeling, how core will now programmatically add aria-current="page" attributes to certain widgets, and programmatically add specific aria-label parameter for navigation menus. Read the dev notes below for more details on the Accessibility focus.

Block Editor

The block editor has continued its rapid iteration since WordPress 5.0, and now has Gutenberg version 6.5 bundled with WordPress 5.3; that’s TWELVE releases all bundled into 5.3 (versions 5.4, 5.5, 5.6, 5.7, 5.8, 5.9, 6.0, 6.1, 6.2, 6.3, 6.4, and 6.5)! Bug fixes and performance improvements from Gutenberg versions 6.6 and 6.7 will also be part of 5.3. The Beta 1 post highlights many of the new features and improvements across these releases, but I’ll specifically pull out the reduction in 1.5 seconds of loading time for a particularly sizeable post (~ 36,000 words, ~ 1,000 blocks) as an impressive achievement given all that has otherwise been added to the block editor. The dev notes below also highlight new server-side block style variations API, a new block example API, the Group block, reduced block styles specificity, using class names for text alignment, Columns block classnames, color support for the separator block, an updates to Table and Gallery blocks markup.


Of the 42 updates for Media in 5.3, you’ll want to particularly note the new way to manage big images by detecting them and generating a “web-optimized maximum size” of them as well as saving of image metadata while creating intermediate sizes. Read the dev notes below for more details on the Media component.


Of the 15 updates for Multisite in 5.3, you’ll want to particularly note changes to the database, changes to WP_MS_Sites_List_Table, return for short circuits for multisite classes, and improved performance for site and network lookups by ID. Read the dev note below for more details on the Multisite component.

PHP 7.4 & Code Modernization

The great news continues. WordPress 5.3 supports PHP 7.4, which is scheduled for release at the end of November! Contributors worked with several external libraries to ensure that all 5 tickets addressing compatibility issues for PHP 7.4 were addressed in time for WordPress 5.3.

In addition to ensuring 5.3 supports PHP 7.4, a handful of updates occurred as a result of the continued coding standards and code modernization efforts. Most notably, the spread operator is now in use where appropriate, and the native PHP JSON extension is now required to run WordPress.

Plugin and theme developers are encouraged to read the following detailed dev notes to fully understand the changes coming and how their code should be updated!


Of the 33 updates for the REST API in 5.3, you’ll want to particularly note register array and object metadata, nested response filtering with _fields query parameter, how to set drafts back to “floating date” status, and possibly best of all up to a 30-40% performance increase in large API responses. Read the dev note below for more details on the REST API component.

Site Health

Of the 31 updates for Site Health in 5.3, you’ll want to particularly note changes to the grading indicator, recovery email enhancements, filters for completed Site Health status tests, and a new Admin email verification screen. Read the dev notes below for more details on the Site Health component.

Other Developer Updates

There are even more goodies in 5.3 like much–needed fixes and a set of improvements to the Date/Time component, changes to prevent search engines indexing sites, new default for links in comments and comment author URLs to use the rel="nofollow ugc" attribute, changes on Twenty Nineteen HTML structure, changes to wp_die() HTML output, expansion of the options available to compare_key so that developers have access to meta-key comparison operators similar to those available for meta values, updates related to bumping the Backbone version bundled with WordPress from v1.3.3 to v1.4.0 and other external library updates, dropping support for integer menu slugs, addition of a “Show” button next to the password field on the login screen, passing arrays to supports argument when registering post types, HTML5 support for script and style arguments, recording additional information for saved queries, unit-less CSS line-height values, updates to cores’ build/test tools, and more! Read through the dev notes below to see what else is coming in 5.3.

But Wait, There is More!

Over 362 bugs, 157 enhancements and feature requests, and 36 blessed tasks have been marked as fixed in WordPress 5.3. Some additional ones to highlight include:

  • General: Use ** operator to replacepow() function calls (#48083)
  • I18n: Text length should be localizable (#44541)
  • Menus: Replace http with https in custom links menu item (#46312)
  • Networks and Sites: Redundant blog_versions table (#19755)
  • Networks and Sites: Save database version in site meta (#41685)
  • Site Health: Provide simple debug data in WSOD emails (#48090)
  • Widgets: Replace http with https in the link placeholder widget image (#46320)

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

#5-3, #field-guide