The issue tracks changes to PHP files that (might) need to be backported and merged to Core for the WordPress 6.4 release. The list is exhaustive so it may cover multiple PRs and experimental changes that won't be in 6.4.

Beta 1 is September 26, 2023

• Release schedule
• 6.4 Roadmap

Tips 👀

• Please open a new Core Trac ticket for each PR and link it next to the citation in this issue. 🙇
• For ease of cross-linking and tracking, you can submit your PRs to WordPress/wordpress-develop. Refer to docs on how to fork the repository and create a PR. Link any backport PR next to the citation in this issue. 🙇
• Try to limit PRs to one feature to make reviewing easier and the commit history clear. See why
• Modifications/additions to PHP unit tests aren't listed: any unit tests introduced in the cited PRs should also be ported over where applicable.
• Once your backport PR is up, add it to the WordPress 6.4 Editor Tasks project board so folks can review it. Thank you!

❗ This is a living document and will be constantly updated as we approach beta. Sorry if you were mistakenly pinged! If a file or files have already been backported, please tick them off and link to the backport PR/trac issue.

Or, if the changes are not slated for WordPress 6.4, you can strike them or make a comment in this issue. Thank you! 🙇

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PRs to be backported will have the "Needs PHP backport" label applied.

📁 lib

📄 blocks.php

• Plugin: Remove 'Footnotes' and 'Comments' from the non-dynamic block registration list #54154 - @Mamaduka | Trac ticket | Core backport PR

📄 class-wp-duotone-gutenberg.php

• Enforce checks against redeclaration for functions and classes #52696 - @anton-vlasenko | Trac ticket | Core backport PR

📄 class-wp-rest-global-styles-controller-gutenberg.php

• Try: bundle WP_REST_Global_Styles_Controller class instead of inheriting per WordPress version #53618 - @ramonjd | Trac ticket | Core backport PR

📄 class-wp-theme-json-gutenberg.php

• Don't add root padding to children of flex and grid layout blocks. #53259 - @tellthemachines | Trac ticket | Core backport PR
• Allow layout controls to be disabled per block from theme.json #53378 - @tellthemachines | Trac ticket | Core backport PR
• Preserve block style variations when securing theme json #53466 - @dsas | Trac ticket | Core backport PR
• get_root_layout_rules: remove unnecessary call to sanitize_title #53568 - @oandregal | Trac ticket | Core backport PR
• Compute presets from theme.json: skip those without classes or variables #53574 - @oandregal | Trac ticket | Core backport PR
• Patterns: Apply layout and alignment to synced patterns in the editor #54416 - @aaronrobertshaw | Trac ticket | Core backport PR
• Image block: UI updates for the image lightbox (redo) #54509 - @artemiomorales | Trac ticket | Core backport PR
• Block custom CSS: Fix incorrect CSS when multiple root selectors #53602 - @t-hamano | Trac ticket (has a patch)

📄 client-assets.php

• Try: Aggressive TinyMCE deprecation #50387 - @tyxla | Trac ticket | Core backport PR (experimental)
• Restore @wordpress/nux to trunk #52455 - @peterwilsoncc | Trac ticket | Core backport PR
• Patterns: create patterns package and share the create pattern modal between post editor and site editor #53161 - @glendaviesnz | Trac ticket | Core backport PR

📄 experiments-page.php

• Experiment: Auto-inserting blocks on the frontend and in the editor (via REST API) #51449 - @ockham | Trac ticket | Core backport PR (experimental)
• Bootstrap a minimal sync package  #52681 - @youknowriad | Trac ticket | Core backport PR (experimental)
• Experiment/add custom connections inspector control #53241 - @c4rl0sbr4v0 | Trac ticket | Core backport PR (experimental) Should not be ported. GB-only and experimental API.

📄 load.php

• Deprecate and make Fonts API non-functional. #52485 - @hellofromtonya | Trac ticket | Core backport PR Plugin only
• Behaviors: Extend Global Styles API to read/write behaviors config. #52370 - @c4rl0sbr4v0 | Trac ticket | Core backport PR (experimental) Should not be ported. It will be reverted in Image block: Revise lightbox UI to remove 'behaviors'
• Patterns: add delete_posts to the wp_block (patterns) capabilities #53405 - @ramonjd | Trac ticket | Core backport PR (Is this going into WP 6.3.2?)
• Fonts Library: Backend #52704 - @matiasbenedetto @hellofromtonya | Trac ticket | Core backport PR
• Relocates Font Face and Fonts Library PHP files into Core's fonts directory #53747 - @hellofromtonya | Trac ticket | Core backport PR
• Patterns: add a custom taxonomy for user created patterns #53163 - @glendaviesnz | Trac ticket | Core backport PR
• Renames "Fonts Library" to "Font Library" #53780 - @matiasbenedetto @hellofromtonya | Trac ticket | Core backport PR
• Font Face: Prepare for merge into Core. #53858 - @matiasbenedetto @hellofromtonya | Trac ticket | Core backport PR
• Date: add relative time translations for moment.js #53931 - @ramonjd | Trac ticket | Core backport PR
• Font Library: Font Collection backend #54098 - @matiasbenedetto @hellofromtonya | Trac ticket | Core backport PR
• Font Face & Font Library: Load PHP files only if the main class does not exist. #54103 - @hellofromtonya | Trac ticket | Core backport PR Plugin only

📄 load.php

• Deprecate and make Fonts API non-functional. #52485 - @hellofromtonya | Trac ticket | Core backport PR Plugin only

📄 theme.json

• Add Typography: text orientation (writing mode) #50822 - @carolinan | Trac ticket | Core backport PR

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📁 block-supports

📁 background.php

• Block Supports: Add background image support to Group block #53934 - @andrewserong | Trac ticket | Core backport PR
• Performance improvement: Reduce the use of the _wp_array_get function #51116 - @aristath | Trac Ticket | Core backport PR

📄 behaviors.php

• Image block: Use built-in directive for mouseover event in lightbox #52067 - @artemiomorales | Trac ticket | Core backport PR (experimental)
• Image block: Remove extra lookup for external image dimensions in lightbox #52178 - @artemiomorales | Trac ticket | Core backport PR (experimental)
• Image block: Add aspect ratio support to lightbox #52765 - @artemiomorales | Trac ticket | Core backport PR (experimental)

📄 colors.php

• Design Tools: Add block instance elements color support for buttons and headings #53667 - @aaronrobertshaw | Trac ticket | Core backport PR

📄 elements.php

• Design Tools: Add block instance elements color support for buttons and headings #53667 - @aaronrobertshaw | Trac ticket | Core backport PR

📄 layout.php

• Block Supports: Re-use instance of Tag Processor when adding layout classes. #54075 - @dmsnell | Trac ticket | Core backport PR

📄 typography.php

• Fluid typography: add min and max viewport width configurable options #53081 - @ramonjd | Trac ticket | Core backport PR

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📁 lib/compat/wordpress-6.4

📄 block-patterns.php

• Patterns: add a custom taxonomy for user created patterns #53163 - @glendaviesnz | Trac ticket | Core backport PR

📄 blocks.php

• Patterns: add delete_posts to the wp_block (patterns) capabilities #53405 - @ramonjd | Trac ticket | Core backport PR (Is this going into WP 6.3.2?)

📄 class-gutenberg-rest-global-styles-revisions-controller-6

• Behaviors: Extend Global Styles API to read/write behaviors config. #52370 - @c4rl0sbr4v0 | Trac ticket | Core backport PR (experimental) Should not be ported. It will be reverted in Image block: Revise lightbox UI to remove 'behaviors'

📄 rest-api.php

• Behaviors: Extend Global Styles API to read/write behaviors config. #52370 - @c4rl0sbr4v0 | Trac ticket | Core backport PR (experimental). Should not be ported. It will be reverted in Image block: Revise lightbox UI to remove 'behaviors'.
• Try: bundle WP_REST_Global_Styles_Controller class instead of inheriting per WordPress version #53618 - @ramonjd | Trac ticket | Core backport PR

📄 script-loader.php

• Date: add relative time translations for moment.js #53931 - @ramonjd | Trac ticket | Core backport PR
• Edit site: prevent enqueuing entire stylesheet in iframe #54254 - @ellatrix | Trac ticket | Core backport PR | Core commit

📄 kses.php

• Gutenberg Plugin: Add hook to allow writing-mode as a safe CSS property #54581 - @t-hamano | Trac ticket (has a patch)

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📁 lib/experimental

📄 auto-inserting-blocks.php

• Experiment: Auto-inserting blocks on the frontend and in the editor (via REST API) #51449 - @ockham | Trac ticket | Core backport PR (experimental)
• Auto-inserting blocks: Minor fixes to address feedback #53183 - @ockham | Trac ticket | Core backport PR (experimental)
• Auto-inserting blocks: Add block inspector panel #52969 - @ockham | Trac ticket | Core backport PR (experimental)

📄 blocks.php

• Allow contents of Paragraph to be "connected" to a meta custom field #53247 - @michalczaplinski | Trac ticket | Core backport PR. Plugin-only and experimental.
• Add filter to turn off Interactivity API for a block #52579 - @westonruter | Trac ticket | Core backport PR (not relevant as Interactivity API is not part of core merge yet)

📄 class--wp-editors.php

• Enforce checks against redeclaration for functions and classes #52696 - @anton-vlasenko | Trac ticket | Core backport PR
• Try: Aggressive TinyMCE deprecation #50387 - @tyxla | Trac ticket | Core backport PR (experimental)

📄 class-gutenberg-rest-block-patterns-controller.php

• Experiment: Auto-inserting blocks on the frontend and in the editor (via REST API) #51449 - @ockham | Trac ticket | Core backport PR (experimental)

📄 class-gutenberg-rest-template-revision-count.php

• Template revisions API: move back to experimental #51774 (Will probably not make 6.4. Blocked by upstream)

📄 class-wp-rest-block-editor-settings-controller.php

• Enforce checks against redeclaration for functions and classes #52696 - @anton-vlasenko | Trac ticket | Core backport PR
• Add caching to schema of REST API. #52045 - @spacedmonkey | Trac ticket | Core backport PR

📄 class-wp-rest-customizer-nonces.php

• Enforce checks against redeclaration for functions and classes #52696 - @anton-vlasenko | Trac ticket | Core backport PR

📄 disable-tinymce.php

• Experimental: Disable TinyMCE compat with classic editor #52325 - @tyxla | Trac ticket | Core backport PR (experimental)
• Experimental: Fix TinyMCE removal for heartbeat requests #52935 - @tyxla | Trac ticket | Core backport PR (experimental)
• Experimental: Backend handle freeform blocks with TinyMCE removal #52938 - @tyxla | Trac ticket | Core backport PR (experimental)

📄 editor-settings.php

• Try: Aggressive TinyMCE deprecation #50387 - @tyxla | Trac ticket | Core backport PR (experimental)
• Remove experimental setting for interactivity API and behaviors #52833 - @c4rl0sbr4v0 | Trac ticket | Core backport PR (experimental) (not relevant as Interactivity API is not part of core merge yet)
• Bootstrap a minimal sync package  #52681 - @youknowriad | Trac ticket | Core backport PR (experimental)
• Experiment/add custom connections inspector control #53241 - @c4rl0sbr4v0 | Trac ticket | Core backport PR (experimental) Should not be ported. GB-only and experimental API.
• Code Quality: Remove gutenberg_initialize_editor #53527 - @ockham | Trac ticket | Core backport PR (experimental)
• Auto-inserting blocks: Add block inspector panel #52969 - @ockham | Trac ticket | Core backport PR (experimental)

📄 kses.php

• Enforce checks against redeclaration for functions and classes #52696 - @anton-vlasenko | Trac ticket | Core backport PR

📄 rest-api.php

• Enforce checks against redeclaration for functions and classes #52696 - @anton-vlasenko | Trac ticket | Core backport PR
• Template revisions API: move back to experimental #51774 (Will probably not make 6.4. Blocked by upstream)

📄 synchronization.php

• Bootstrap a minimal sync package  #52681 - @youknowriad | Trac ticket | Core backport PR (experimental)

### 📁 lib/experimental/fonts-api
The Fonts API will not be backported to Core, as it's been deprecated in the plugin and replaced by Font Face.

#### 📄 fonts-api.php

• Fix font printing regression when metabox exists #52343 - @hellofromtonya | Trac ticket | Core backport PR

📁 lib/experimental/fonts/font-library

📄 class-wp-font-library.php

• Font Library: changing the upload directory to wp-content/fonts #54122 - @jffng @matiasbenedetto | Trac ticket | Core backport PR
• Font Library: add mime type validation for font uploads #53986 - @madhusudhand | Trac ticket | Core backport PR

📄 class-wp-font-family.php

• Font Library: fix duplicate variants with different file types #54490 - @jffng | Trac ticket | Core backport PR
• Font Library: setting wp_font_family custom post type as _builtin and not plublic #54559 - @matiasbenedetto | Trac ticket | Core backport PR
• Font Library: remove upload_mimes filter after uploading fonts #54647 - @madhusudhand | Trac ticket | Core backport PR

📄 class-wp-font-family-utils.php

• Font Library: ensure merged fontFace data is enconded as an array instead of an object #54435 - @matiasbenedetto | Trac ticket | Core backport PR

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📁 fonts-library

• Fonts Library: Test improvements #53702 - @hellofromtonya | Trac ticket | Core backport PR
• Font Library: Font Collections frontend #54566 - @matiasbenedetto | Trac ticket | Core backport PR
• Font Face: Get name from "fontFamily" setting, not "name". #54615 - @hellofromtonya | Trac ticket | Core backport PR | Core commit

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📁 packages/style-engine

📄 packages/style-engine/class-wp-style-engine.php

• Style engine: update docs for css_var #53710 - @ramonjd | Trac ticket | Core backport PR
• Design Tools: Add block instance elements color support for buttons and headings #53667 - @aaronrobertshaw | Trac ticket | Core backport PR
  

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📁 packages/block-serialization-default-parser

📄 class-wp-block-parser.php

• Block API: Unnecessary JSON decoding in block parser #54424 - @spacedmonkey | Trac ticket | Core backport PR

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📁 packages/block-library/

• Patterns: Remove pattern category as a variation for post terms block #54532 - @glendaviesnz | Trac ticket | Core backport PR

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🚧 Contingent features

The following are features that may or may not be shipped with 6.4.