Today’s edition of What’s new for developers? marks six months of the extender-focused roundup here on the WordPress Developer Blog. So break out the party hats, champagne glasses, and cake. You can’t celebrate without cake.
It couldn’t come at a better time. This is a big post, filled with lots of developer goodies.
Which is what you’d expect—WordPress 6.3 is only a month away. Officially, the launch date is August 8, 2023. There will also be a live product demo on July 20, 2023.
Speaking of WordPress 6.3, that release will officially drop support for PHP 5. After August 8, you will need to run PHP 7.0.0 or newer to use WordPress.
Table of Contents
Phase 3 updates
Gutenberg lead architect Matías Ventura posted four updates on his March 2023 Phase 3: Collaboration outline.
The four posts will keep you current on the roadmap to what are arguably the biggest changes to the editorial workflow that WordPress has ever seen:
- Real-Time Collaboration covers plans for concurrent collaboration, shared edits, visibility of peers, and lifting current editing restrictions.
- Workflows imagines seamless collaboration over the whole editorial process, from first draft through publication and beyond.
- Revisions proposes a complete overhaul of the current system in favor of one that works with blocks and tracks changes on every data layer, from the server stack to the user’s latest edits.
- Media Library aims to expand media management capabilities, unify the interfaces and improve overall media workflows.
Throughout the posts, Matías makes it clear that these are early days. Phase 3 is an audacious plan that will change publishing as we know it, and it will need your ideas (and code!) to come to life.
The Command Palette, formerly the Command Center, now has a public API. This means you can extend it to add custom commands in your themes and plugins, or even unregister core commands.
The palette puts commands at your fingertips that control these areas:
- Templates, parts, and styles
- Custom patterns
- Global styles
- The post editor UI
- Preferences and keyboard shortcuts
- Edit template and back-to-page
- And more…
Block spacing and CSS-Grid layouts for Post Template
Gutenberg 16.0 brought a major change to how the layout works for the Query Loop and its nested Post Template block.
Before 16.0, the grid options used the CSS Flexbox module (and its wrap option to lay posts out in columns.
Now the feature has true CSS-Grid support. To most people, the block doesn’t look all that different. But for you, it opens up the entire CSS-Grid specification for you to use in custom block styles.
As well, now you can control the block spacing between posts in either the list or grid views. Before 16.0, this was a hardcoded value that rarely matched the theme’s spacing rules.
A new Footnotes block landed in Gutenberg 16.1, letting you insert a footnote link in any RichText area. Once the link is there, it shows you a footnote list at the bottom of the post. There you can edit each footnote’s content.
For the most part, this is a user-facing change, but you can style the block to match your theme.
Plugins and tools
WordPress development mode
WordPress 6.3 will bring you a
WP_DEVELOPMENT_MODE constant, to signify a context-specific development mode, that you can set to
plugin. Setting the constant to an empty string will mean you’re not using a development mode..
Plus, a new
wp_get_development_mode() function will return the value of the constant.
What’s this mode good for?
If you’ve ever had
theme.json caches disrupt your workflow when you were elbows-deep in a theme, now you can set your development mode to turn off caching programmatically.
In the future, you might use these modes for clearer error messages—or build your own tooling.
Set async and defer attributes on scripts
Right now, if you want a script to load in the footer, you can do that with a boolean.
In 6.3, though, you’ll be able to use an array in the
$in_footer parameter of
wp_enqueue_script(). That array will take this form:
array( 'strategy' => 'defer', // or 'async' 'in_footer' => true // or false )
Post editor iframe is back
The post editor iframe is back, as of Gutenberg 16.0. Did you miss it? You’ll need to set all your registered blocks to API version 3 in their
block.json files. You should probably update those versions anyway—unless, of course, you have a reason for some of your custom blocks to hang back at version 2.
If you were previously using the
HeadingLevelDropdown component is here, to use in your own blocks. It lets users select headers from H1-H6, or a paragraph tag. The new component is separate from the Heading block, so you can reuse core code.
Button component has a new
size property you can set to
compact (32px), or
default (36px). The
default prop will be 40px when
__next40pxDefaultSize is set to
Toolbar component now uses Ariakit, the successor to the previously-used Reakit. You should see better performance and fewer bugs. Your toolbar interactions should behave as they do now, but test your custom blocks.
Check if theme supports the Site Editor
is_block_theme property lets you check exactly that in the REST API, courtesy of the
wp/v2/themes API response.
Action and filter hooks
Several new hooks will land in WordPress 6.3:
plugins_list: Now you can manipulate the list of plugins that show on the Plugins screen.
bulk_edit_posts: An action hook that fires after post data is processed but before the results of the bulk edit are returned.
wp_update_user_action: An action hook that fires after a user has been updated and emails have been sent.
nav_menu_item_attributes: A filter hook for passing attributes to nav menu items.
nav_menu_submenu_attributes: A filter hook for passing attributes to sub-menus within a nav menu.
Plus, you’ll have a new parameter,
$previous_status, to pass to existing trash hooks—
Enhanced performance for first large image
In May, the Performance Team proposed adding the
fetchpriority="high" attribute to speed up Largest Contentful Paint images.
A solution has now merged into Core that adds the attribute to the first image on a page that is neither lazy-loaded nor has a conflicting
fetchpriority attribute, and has dimensions greater than 50,000 square pixels.
Better block render path detection in watch mode
start command is running with
@wordpress/wp-scripts, a new webpack plugin handles updating the block render paths defined in
block.json. Essentially, it is a more performant way to find changes to the file. The best part? You get the speed improvements by simply using the scripts package—with no extra updates to code or anything.
The Classic and Shortcode blocks no longer convert HTML entities when they are parsed. This change prevents bugs based on the library used for parsing HTML.
Up to now, you could choose multiple authors in the Query Loop Block. But you’d only get posts from the first one. A recent patch should fix that behavior in WordPress 6.3.
Relevant user interface changes
Now you can edit and create new pages in the Site Editor—just pick Pages in the menu. If your plugins hook into the content creation process, you’ll want to test them for compatibility.
New source attribute for block patterns
source attribute has come to the Block Patterns API that lets themes, plugins, core, and other sources define where the pattern is coming from. If you are registering patterns from a theme, your
source attribute should be
theme. For plugins, use
Descriptions for style variations
Global style variations, defined in a theme’s
/styles folder, now have a
description property for better accessibility. Use it to give screen readers more information on your design; before, all you had was the title.
Classic theme support improvements
Classic themes are getting some love in WordPress 6.3:
- The core
classic-themes.cssstylesheet now renders inline. That means one fewer HTTP request, and correspondingly better performance, on millions of sites.
- You can now add theme support for borders in the editor.
- You can also add theme support for link color settings.
Post Content block is back in the post editor! (Sort of)
Gutenberg 15.9 took the Post Content block out of the post editor, because the editor canvas is the content. But that change also meant you could not use the Query Loop block to showcase content from other posts and pages.
In Gutenberg 16.1, the Post Content block is back for the post editor, but you can only use it inside a Query Loop block.
Non-root sticky positioning
Tweak return values of gutenberg_get_global_styles()
In WordPress 6.2, the
gutenberg_get_global_styles() function returns the CSS value, not the custom property defined in
For example, if you wanted to get a font size, the function returns
var( --wp--preset--font-size--medium ). Depending on what else you were doing, that could have been an unexpected result.
There’s been a change that adds a
transforms key that lets you set the data format. For now, it accepts one value in the form of
array( 'resolve-variables' ), and you can transform the value to its custom property. You might see more transforms added in the future.
theme.json layout definitions support removed
Layout definitions are gone from
theme.json in Gutenberg 16.1. Previously,
settings.layout.definitions gave you ways to extend or override some core rules. But that never got any official support. And inclusion has bred some bugs. If you have used these definitions in the past, you’ll want to take them out of your
Note that this does not affect customizing the content and wide sizes in
Textdomain loading is gone from core themes
WordPress has supported just-in-time translation loading since version 4.6, and theme authors haven’t needed to call
load_theme_textdomain() since that release. This function call is no longer in any default theme from Twenty Seventeen on.
Several bug fixes related to themes landed in Gutenberg and core WordPress in the last month:
- The max viewport width is now correctly used in the editor when you enable fluid typography.
- The Post Content block’s layout settings should now always be correct in the post editor.
- The change to grid layout for the Post Template block initially pulled the columns class out of Core, but now it’s back, for backward compatibility.
- A caching issue in
WP_Theme::get_post_templates(), where block templates were incorrectly cached, has been fixed.
Noteworthy user-facing changes
Music streaming platform Anghami is now on the list of trusted oEmbed providers. There is no specific block variation for it yet, but you can still show songs and playlists in the Embed block.
The Global Styles revisions system has moved from the experimental stage and will ship with WordPress 6.3.
Proposals, events, and resources
Here are a couple of major proposals that you should read. Please join these discussions—they will affect how you build on top of WordPress for years to come:
Two new tutorials and one new course have arrived on Learn WP in the past month:
- Tutorial: How to start using WordPress Playground
- Tutorial: Advanced Multisite Management
- Course: Introduction to Developing with the WordPress REST API
Hallway Hangouts and Developer Hours
In June, two events showcased best practices for extending the block editor:
- Hallway Hangout: Let’s chat about WordPress 6.3 and block theming
- Developer Hours: Exploring Editor Extensibility
Four new posts went live in the last 30 days:
- How to modify theme.json data using server-side filters
- The Style Book: a one-stop shop for styling block themes
- Navigating the Block Editor Handbook
- Upgrading the site-editing experience with custom template part areas