5.0.0

Features

• Add a new RSS block and follow-up improvements: 1, 2.
• Add a new Amazon Kindle embed block.
• Add a new FocalPointPicker component and use it to define the focal point of the Cover block background.

Enhancements

• Optimize the re-rendering performance when inserting/removing blocks.
• Improve the Reusable Blocks UX for contributor users.
• Disable embed previews for the smugmug provider.
• Make the fullscreen mode a desktop-only feature.
• Accessibility: Add speak messages when using the FeatureToggle component.
• Accessibility: Change the inserter search result message from assertive to polite.
• Accessibility: Remove duplicate aria label from menu items.
• Remove the "Show Download Button" toggle help text in the File block.
• Render the block switcher as disabled if not available in a multi-selection.
• Use a back arrow icon to clarify the Fullscreen mode exit button.
• Limit the Gallery block columns count to the images count.
• Automatically set a default block style if missing.
• Hide empty categories from the Categories block in the editor.
• Increase the padding of the gallery captions.
• Add left/right alignments to the latest posts block.
• Improve the columns margins.
• Add a help text for the hide teaser toggle in the More block.
• Improve the wording of the embed block messages.

Bug Fixes

• Accessibility: Fix the tab order of the date picker component.
• Support non hierarchical taxonomies in the category selector component.
• Fix blocks marked invalid incorrectly due to special HTML characters.
• Fix the Notice component styling.
• Fix the :root selector in the editor styles.
• Fix duplicate block toolbars.
• Fix warning message when using the DateTimePicker component.
• Fix the File block and Categories block style when applying custom classnames.
• Fix the Gallery block styling in Microsoft Edge.
• Fix the Button block styling when links are visited.
• Fix Block Style preview not dismissed after selection.
• Fix TabPanel buttons incorrectly submitting forms.
• Fix hierarchical dropdown in the Categories block.
• Fix wording for the color picker saturation.
• Fix the save keyboard shortcut while in the code editor mode.
• Fix the Google Docs table pasting.
• Fix jumps when indenting/outdenting list items.
• Fix FontSizePicker max width on mobile.
• Fix PHP 5.2.2 Parser issue.
• Fix plural messages POT generation.

Various

• Add ESnext build setup and commands to the @wordpress/scripts package.
• Add "focus on mount" config to the DropDown component.
• Improve the error handling in the data module resulting in clearer messages displayed in the console.
• Support marking days as invalid in the DatePicker component.
• Support block transforms with inner blocks.
• Improve the styles of the editor notices with actions.
• Replace Polldaddy embed block with Crowdsignal.
• Avoid setting the generic Edit Post Title on load.
• Deprecate window._wpLoadGutenbergEditor.
• Avoid an empty classname when deleting custom classnames.
• Add className prop support to the ServerSideRender component.

Documentation

• Improve the components README files DropdownMenu & RangeControl.
• Add code example of the MediaPlaceholder component.
• Add a accessibility dedicated page.
• Add a Git workflow documentation page.
• Reorganize the contributors guide.
• Mention the dark theme support in the design docs.
• Enhance the compose package documentation.
• Expand the block templates code examples.
• Fix unregisterBlockType code examples.
• Clarify the block styles isDefault property.
• Move the npm packages management documentation to a dedicated page.
• Add a section explaining the links usage in the documentation.
• Add a note about the wp-editor dependency when using RichText.
• Update the isShallowEqual package documentation and tests.
• Refresh the repository management doc.
• Typos: 1, 2, 3, 4, 5, 6, 7.

Chore

• Remove PHP Code maintained in Core and bump minimum WordPress version:
  • Block registration.
  • REST API Endpoints.
  • Markdown support fix.
  • Gutenberg body classname and responsive classname.
  • Preloading API calls.
  • Block detection utilities.
  • List screen integration.
  • Block content version.
  • Block categories hook.
  • TinyMCE scripts registration.
  • Reusable blocks post type labels and listing page.
  • Block Types Initialization.
  • PHP Unit tests.
  • Compatibility script.
  • Meta boxes support.
  • Polyfills.
  • oEmbed Proxy Endpoint filter.
  • Visual Editing Disabling.
• Update [browserlist dependency](https://github.com/WordPre...

5.0.0 Release Candidate

Features

• Add a new RSS block and follow-up improvements: 1, 2.
• Add a new Amazon Kindle embed block.
• Add a new FocalPointPicker component and use it to define the focal point of the Cover block background.

Enhancements

• Optimize the re-rendering performance when inserting/removing blocks.
• Improve the Reusable Blocks UX for contributor users.
• Disable embed previews for the smugmug provider.
• Make the fullscreen mode a desktop-only feature.
• Accessibility: Add speak messages when using the FeatureToggle component.
• Accessibility: Change the inserter search result message from assertive to polite.
• Accessibility: Remove duplicate aria label from menu items.
• Remove the "Show Download Button" toggle help text in the File block.
• Render the block switcher as disabled if not available in a multi-selection.
• Use a back arrow icon to clarify the Fullscreen mode exit button.
• Limit the Gallery block columns count to the images count.
• Automatically set a default block style if missing.
• Hide empty categories from the Categories block in the editor.
• Increase the padding of the gallery captions.
• Add left/right alignments to the latest posts block.
• Improve the columns margins.
• Add a help text for the hide teaser toggle in the More block.
• Improve the wording of the embed block messages.

Bug Fixes

• Accessibility: Fix the tab order of the date picker component.
• Support non hierarchical taxonomies in the category selector component.
• Fix blocks marked invalid incorrectly due to special HTML characters.
• Fix the Notice component styling.
• Fix the :root selector in the editor styles.
• Fix duplicate block toolbars.
• Fix warning message when using the DateTimePicker component.
• Fix the File block and Categories block style when applying custom classnames.
• Fix the Gallery block styling in Microsoft Edge.
• Fix the Button block styling when links are visited.
• Fix Block Style preview not dismissed after selection.
• Fix TabPanel buttons incorrectly submitting forms.
• Fix hierarchical dropdown in the Categories block.
• Fix wording for the color picker saturation.
• Fix the save keyboard shortcut while in the code editor mode.
• Fix the Google Docs table pasting.
• Fix jumps when indenting/outdenting list items.
• Fix FontSizePicker max width on mobile.
• Fix PHP 5.2.2 Parser issue.
• Fix plural messages POT generation.

Various

• Add ESnext build setup and commands to the @wordpress/scripts package.
• Add "focus on mount" config to the DropDown component.
• Improve the error handling in the data module resulting in clearer messages displayed in the console.
• Support marking days as invalid in the DatePicker component.
• Support block transforms with inner blocks.
• Improve the styles of the editor notices with actions.
• Replace Polldaddy embed block with Crowdsignal.
• Avoid setting the generic Edit Post Title on load.
• Deprecate window._wpLoadGutenbergEditor.
• Avoid an empty classname when deleting custom classnames.
• Add className prop support to the ServerSideRender component.

Documentation

• Improve the components README files
  • DropdownMenu.
  • RangeControl.
  • Add code example of the MediaPlaceholder component.
• Add a accessibility dedicated page.
• Add a Git workflow documentation page.
• Reorganize the contributors guide.
• Mention the dark theme support in the design docs.
• Enhance the compose package documentation.
• Expand the block templates code examples.
• Fix unregisterBlockType code examples.
• Clarify the block styles isDefault property.
• Move the npm packages management documentation to a dedicated page.
• Add a section explaining the links usage in the documentation.
• Add a note about the wp-editor dependency when using RichText.
• Update the isShallowEqual package documentation and tests.
• Refresh the repository management doc.
• Typos: 1, 2, 3, 4, 5, 6, 7.

Chore

• Remove PHP Code maintained in Core and bump minimum WordPress version:
  • Block registration.
  • REST API Endpoints.
  • Markdown support fix.
  • Gutenberg body classname and responsive classname.
  • Preloading API calls.
  • Block detection utilities.
  • List screen integration.
  • Block content version.
  • Block categories hook.
  • TinyMCE scripts registration.
  • Reusable blocks post type labels and listing page.
  • Block Types Initialization.
  • PHP Unit tests.
  • Compatibility script.
  • Meta boxes support.
    ...

4.9.0

Changelog

Performance

• Implement an async rendering mode for the data module updates.
• Avoid rerendering the block components when selecting a block.
• Improve the performance of isEditorEmptyPost selector (13% typing performance improvement).
• Data Module: Avoid persisting unchanged values.
• Update withSelect to use type-optimized isShallowEqual.
• Move data selection to event handlers (called only when necessary).
• Improve the initial rendering time by optimizing the withFilters Higher-order component.

Bug Fixes

• Fix RichText toolbar when using multiline=”li”.
• Correct the margin of the block icons in the inserter.
• Fix ampersand in post tags causing editor crash.
• Remove alignundefined class from gallery block edit markup.
• Disable the button to open the publish sidebar if locked.
• Correct the default margin for buttons with icons.
• Keep the date floating when for posts with "pending" status.
• Fix using the EXIF title when uploading images.
• Fix font size picker on mobile.
• Fix z-index of the Reusable Block Inserter button.
• Fix autop behavior when a text is followed by a div.
• Fix warning when returning null from a data module generator.
• Announce the screen reader messages in the correct order in Safari.
• Check Post Type support in the options modal.

Enhancements

• Support customizing the table background colors.
• Support underlining text using the keyboard shortcut ctrl+U.
• Apply the editor styles to the HTML Block Preview.
• Improve the color swatch selection indicator.
• Improve scrolling behavior in Fullscreen Mode in Edge.
• Remove deprecated embed providers.
• Refactor the alignements support in the Cover Block and the Categories Block.
• Code quality improvement to getBlockContentSchema
• Internationalize the excerpt documentation link.
• Improve pasting of quotes with citations.
• A11y
  • Add a tooltip to the block list appender.
  • Improve the color contrast of the inserter shortcuts.
  • Remove the label from the Warning component’s menu.
• Add an option to overwrite the block in the Warning component.

Extensibility

• Support custom fetch handlers for wp.apiFetch.
• Support additional data passed to the mediaUpload utility.
• Add filter for the preview interstitial markup.
• Avoid appending empty query string in wp.url.addQueryArgs.
• Dispatch heartbeat events as hook actions to avoid the jQuery dependency.
• Support adding classnames to the plugins sidebar panels.
• Add a className to the parent page selector.

Documentation

• Add tutorials for
  • Creating sidebar plugins.
  • Using the Format API.
  • Creating meta blocks.
• Reorganize the tutorials page.
• Improve the UI component documentation:
  • The ButtonGroup component.
  • The IconButton component.
  • The SelectControl component.
  • The TextareaControl component.
  • The TabPanel component.
  • The Toolbar component.
  • The FormToggle component.
• Update the Gutenberg Release and the Repository Management docs.
• Add new section on scoping JS code.
• Use Block Editor instead of Gutenberg in the docs.
• Mention the Advanced Controls Panel in the design guidelines.
• Clarify the unregisterBlockStyle documentation.
• Clarify the difference between the button block and the button component.
• Scope JavaScript ES5 code example.
• Fix incorrect code example.
• Clarify the deprecated APIs.
• Fix typos 1 2 3 4 5 6 7.

Chore

• Improve CI build times.
• Extract error messages from console logging in E2E tests.
• Reorganization of the E2E tests setup and expose it as npm packages.
• Add aXe accessibility E2E tests support.
• Add E2E tests for the excerpt meta box plugin.

Mobile

• Fix the Image Size implementation.
• Fix scrolling long text content.

4.9.0 Release Candidate

Performance

• Implement an async rendering mode for the data module updates.
• Avoid rerendering the block components when selecting a block.
• Improve the performance of isEditorEmptyPost selector (13% typing performance improvement).
• Data Module: Avoid persisting unchanged values.
• Update withSelect to use type-optimized isShallowEqual.
• Move data selection to event handlers (called only when necessary).
• Improve the initial rendering time by optimizing the withFilters Higher-order component.

Bug Fixes

• Fix RichText toolbar when using multiline=”li”.
• Correct the margin of the block icons in the inserter.
• Fix ampersand in post tags causing editor crash.
• Remove alignundefined class from gallery block edit markup.
• Disable the button to open the publish sidebar if locked.
• Correct the default margin for buttons with icons.
• Keep the date floating when for posts with "pending" status.
• Fix using the EXIF title when uploading images.
• Fix font size picker on mobile.
• Fix z-index of the Reusable Block Inserter button.
• Fix autop behavior when a text is followed by a div.
• Fix warning when returning null from a data module generator.
• Announce the screen reader messages in the correct order in Safari.
• Check Post Type support in the options modal.

Enhancements

• Support customizing the table background colors.
• Support underlining text using the keyboard shortcut ctrl+U.
• Apply the editor styles to the HTML Block Preview.
• Improve the color swatch selection indicator.
• Improve scrolling behavior in Fullscreen Mode in Edge.
• Remove deprecated embed providers.
• Refactor the alignements support in the Cover Block and the Categories Block.
• Code quality improvement to getBlockContentSchema
• Internationalize the excerpt documentation link.
• Improve pasting of quotes with citations.
• A11y
  • Add a tooltip to the block list appender.
  • Improve the color contrast of the inserter shortcuts.
  • Remove the label from the Warning component’s menu.
• Add an option to overwrite the block in the Warning component.

Extensibility

• Support custom fetch handlers for wp.apiFetch.
• Support additional data passed to the mediaUpload utility.
• Add filter for the preview interstitial markup.
• Avoid appending empty query string in wp.url.addQueryArgs.
• Dispatch heartbeat events as hook actions to avoid the jQuery dependency.
• Support adding classnames to the plugins sidebar panels.
• Add a className to the parent page selector.

Documentation

• Add tutorials for
  • Creating sidebar plugins.
  • Using the Format API.
  • Creating meta blocks.
• Reorganize the tutorials page.
• Improve the UI component documentation:
  • The ButtonGroup component.
  • The IconButton component.
  • The SelectControl component.
  • The TextareaControl component.
  • The TabPanel component.
  • The Toolbar component.
  • The FormToggle component.
• Update the Gutenberg Release and the Repository Management docs.
• Add new section on scoping JS code.
• Use Block Editor instead of Gutenberg in the docs.
• Mention the Advanced Controls Panel in the design guidelines.
• Clarify the unregisterBlockStyle documentation.
• Clarify the difference between the button block and the button component.
• Scope JavaScript ES5 code example.
• Fix incorrect code example.
• Clarify the deprecated APIs.
• Fix typos 1 2 3 4 5 6 7.

Chore

• Improve CI build times.
• Extract error messages from console logging in E2E tests.
• Reorganization of the E2E tests setup and expose it as npm packages.
• Add aXe accessibility E2E tests support.
• Add E2E tests for the excerpt meta box plugin.

Mobile

• Fix the Image Size implementation.
• Fix scrolling long text content.

🚩4.8.0

Performance

• Improve page initialization time by optimizing the addHook function and the viewport state initialization.
• Improve typing performance by splitting the state tree.
• Optimize partial application of runSelector.
• Move selector calls to the event handles to avoid useless component rerenders.
• Render DropZone children only when dragging elements over it.
• Initialize variables only when needed.

Enhancements

• Add error messages to the image block on upload failures.
• Merge similar i18n strings.
• Disable clipboard button in file block during upload.
• Persist alignment when transforming a gallery to an image and vice-versa.
• Copy enhancement to the embed block help text.
• Improve the scrolling of the WordPress navigation menu.

Bug Fixes

• Fix RTL support for the DatePicker component.
• Change the header level in the BlockCompare component.
• Show all the taxonomies in the sidebar.
• Fix the latest posts date className.
• Fix the “align center” button in Latest Posts block in the backend.
• Fix block height when DropCap is used.
• Fix converting caption shortcode with link.
• Fix edge case in addQueryArgs function.
• Don’t return the permalink if the CPT is not publicly viewable.
• Fix error when saving non public CPTs.
• Properly disable the Publish button when saving is disabled.

Various

• Show a message in the browser’s console when in Quirks Mode.
• Improvements to the @wordpress/scripts package: A new a check-engines command, a lint-style command and an update to lint-js.

Documentation

• Add a getting started with JavaScript tutorial.
• Document the blocks’ setup states in the design guidelines.
• Add content to Contributors index page.
• Improve the components documentation:
  • The MenuItem component.
  • The RadioControl component.
  • The ServerSideRender component.
• Organise the documentation assets in a dedicated folder.
• Clarify immutability of the block attributes.
• Fix the metabox back compat code example.
• Fix incorrect data module example.
• Improve the plugin release docs.
• Remove useless property from the colors code example.
• Improve the contributing documentation.
• Fix npm README links.
• Update the design resources link.
• Typo fixes.

Chore

• Run e2e tests with popular plugins enabled.
• Add new e2e tests:
  • The permalink panel.
  • The categories panel.
  • Blocks with meta attributes.
• Update node-sass to fix Node 11 support.
• Move the dev dependencies to the root package.json.
• Improve the Pull Request Template.
• More logs to the CI jobs.
• Code style fixes and expand the phpcs coverage.
• Disable fragile e2e tests.
• Avoid PHP notices when running the e2e tests in debug mode.

Mobile

• Make a simple version of DefaultBlockAppender.
• Stop using classname-to-style autotransform in react native.
• Fix SVG styles.
• Implement Enter press to add a default block.
• Hide keyboard when non textual block is selected.
• Fix undo/redo on new blocks.
• Pass the blockType prop to RNAztecView.
• Expose unregisterBlockType.

4.8.0 Release Candidate

Performance

• Improve page initialization time by optimizing the addHook function and the viewport state initialization.
• Improve typing performance by splitting the state tree.
• Optimize partial application of runSelector.
• Move selector calls to the event handles to avoid useless component rerenders.
• Render DropZone children only when dragging elements over it.
• Initialize variables only when needed.

Enhancements

• Add error messages to the image block on upload failures.
• Merge similar i18n strings.
• Disable clipboard button in file block during upload.
• Persist alignment when transforming a gallery to an image and vice-versa.
• Copy enhancement to the embed block help text.
• Improve the scrolling of the WordPress navigation menu.

Bug Fixes

• Fix RTL support for the DatePicker component.
• Change the header level in the BlockCompare component.
• Show all the taxonomies in the sidebar.
• Fix the latest posts date className.
• Fix the “align center” button in Latest Posts block in the backend.
• Fix block height when DropCap is used.
• Fix converting caption shortcode with link.
• Fix edge case in addQueryArgs function.
• Don’t return the permalink if the CPT is not publicly viewable.
• Fix error when saving non public CPTs.
• Properly disable the Publish button when saving is disabled.

Various

• Show a message in the browser’s console when in Quirks Mode.
• Improvements to the @wordpress/scripts package: A new a check-engines command, a lint-style command and an update to lint-js.

Documentation

• Add a getting started with JavaScript tutorial.
• Document the blocks’ setup states in the design guidelines.
• Add content to Contributors index page.
• Improve the components documentation:
  • The MenuItem component.
  • The RadioControl component.
  • The ServerSideRender component.
• Organise the documentation assets in a dedicated folder.
• Clarify immutability of the block attributes.
• Fix the metabox back compat code example.
• Fix incorrect data module example.
• Improve the plugin release docs.
• Remove useless property from the colors code example.
• Improve the contributing documentation.
• Fix npm README links.
• Update the design resources link.
• Typo fixes.

Chore

• Run e2e tests with popular plugins enabled.
• Add new e2e tests:
  • The permalink panel.
  • The categories panel.
  • Blocks with meta attributes.
• Update node-sass to fix Node 11 support.
• Move the dev dependencies to the root package.json.
• Improve the Pull Request Template.
• More logs to the CI jobs.
• Code style fixes and expand the phpcs coverage.
• Disable fragile e2e tests.
• Avoid PHP notices when running the e2e tests in debug mode.

Mobile

• Make a simple version of DefaultBlockAppender.
• Stop using classname-to-style autotransform in react native.
• Fix SVG styles.
• Implement Enter press to add a default block.
• Hide keyboard when non textual block is selected.
• Fix undo/redo on new blocks.
• Pass the blockType prop to RNAztecView.
• Expose unregisterBlockType.

4.7.1

Changelog

• Fix editor.BlockListBlock filter regression caught using the ACF pro beta plugin

4.7.0

Changelog (Same as RC)

Performance improvements

• Optimize isViewportMatch
• Performance: BlockListAppender: 1.7x increase on key press
• Date: Optimize the usage of moment-timezone to save some kilobytes
• RichText: selectionChange: bind on focus, unbind on blur
• RichText: only replace range and nodes if different
• Cache createBlock call in isUnmodifiedDefaultBlock
• Edit Post: Select blocks only once multiple verified
• RichText: Do not run valueToEditableHTML on every render
• RichText: Reuse DOM document across calls to createEmpty
• Only initialise TinyMCE once per instance
• Optimize the insertion point component
• Avoid rerending the current block if the previous block change
• Avoid getBlock in block-list/block
• Pass the registry argument to withDispatch to allow selectors to be used

Bug fixes

• Annotations: Apply annotation className as string
• RichText: Ensure instance is selected before setting back selection
• Meta Boxes: Don’t hide disabled meta boxes by modifying DOM
• Fix: Problems on Media & Text block resizing; Load wp-block-library styles before wp-edit-blocks
• When a post is saved, check for tinymce and save any editors.
• Fix: Undoing Image Selection from Media Library in Image Block breaks it
• Add an end-to-end test for the HTML block
• Fix regression when copying or cutting content in the editor
• Fix issue where default appender has icons overlaying the text
• Set document title for preview loading interstitial
• Fix: Upload permissions error on end-to-end inline tokens test
• Ensure classic block caret is in correct position after blur
• Fix tab navigation sometimes skipping block UI
• Improve font size picker accessibility: Use a menuitemradio role and better labels
• Don’t show trashed reusable blocks in the editor or frontend
• Rename functions, removing gutenberg_ prefix
• Add block switcher end-to-end tests
• Allow links in plugin group in the editor more menu
• Introduce searching of block categories from slash inserter
• Convert HTML formatting whitespace to spaces
• Label link format with selected text, not full text
• Ensure permalink panel is only displayed when a permalink is allowed
• Allow the user to convert unembeddable URLs to links and try embedding again
• Improve the top bar tools interaction and consistency
• Fix overflowing content in the facebook embed preview screen
• Add an action to set a category icon and correct block categories documentation
• Fix: pasting a tag that is part of a transform and not matched ignores the content.
• Packages: Extract Eslint config package
• Add end-to-end test to catch revert of title during a preview after saving a draft
• Avoid react warnings when merging two adjacent paragraphs
• Avoid PHP notice in the recent comments block

4.7.0 Release Candidate 🏎

Changelog

Performance improvements

• Optimize isViewportMatch
• Performance: BlockListAppender: 1.7x increase on key press
• Date: Optimize the usage of moment-timezone to save some kilobytes
• RichText: selectionChange: bind on focus, unbind on blur
• RichText: only replace range and nodes if different
• Cache createBlock call in isUnmodifiedDefaultBlock
• Edit Post: Select blocks only once multiple verified
• RichText: Do not run valueToEditableHTML on every render
• RichText: Reuse DOM document across calls to createEmpty
• Only initialise TinyMCE once per instance
• Optimize the insertion point component
• Avoid rerending the current block if the previous block change
• Avoid getBlock in block-list/block
• Pass the registry argument to withDispatch to allow selectors to be used

Bug fixes

• Annotations: Apply annotation className as string
• RichText: Ensure instance is selected before setting back selection
• Meta Boxes: Don’t hide disabled meta boxes by modifying DOM
• Fix: Problems on Media & Text block resizing; Load wp-block-library styles before wp-edit-blocks
• When a post is saved, check for tinymce and save any editors.
• Fix: Undoing Image Selection from Media Library in Image Block breaks it
• Add an end-to-end test for the HTML block
• Fix regression when copying or cutting content in the editor
• Fix issue where default appender has icons overlaying the text
• Set document title for preview loading interstitial
• Fix: Upload permissions error on end-to-end inline tokens test
• Ensure classic block caret is in correct position after blur
• Fix tab navigation sometimes skipping block UI
• Improve font size picker accessibility: Use a menuitemradio role and better labels
• Don’t show trashed reusable blocks in the editor or frontend
• Rename functions, removing gutenberg_ prefix
• Add block switcher end-to-end tests
• Allow links in plugin group in the editor more menu
• Introduce searching of block categories from slash inserter
• Convert HTML formatting whitespace to spaces
• Label link format with selected text, not full text
• Ensure permalink panel is only displayed when a permalink is allowed
• Allow the user to convert unembeddable URLs to links and try embedding again
• Improve the top bar tools interaction and consistency
• Fix overflowing content in the facebook embed preview screen
• Add an action to set a category icon and correct block categories documentation
• Fix: pasting a tag that is part of a transform and not matched ignores the content.
• Packages: Extract Eslint config package
• Add end-to-end test to catch revert of title during a preview after saving a draft

4.6.1

Changelog

• Parser: Make attribute parsing possessive (Fix High CPU usage).