CKEditor 5 changelog

This is the CKEditor 5 changelog guide. Here you will find information about the most important changes introduced in the release, new features, and bug fixes.

Information about both major and minor breaking changes is available, too, if the release introduces them. You can read more about breaking changes in CKEditor 5 in the Versioning policy guide.

You can find more information about each release in the blog posts linked at the start of each entry.

This guide provides the changelog information for the 3 latest releases of CKEditor 5. For older releases, refer to the release notes on GitHub.

We are happy to announce the release of CKEditor 5 v48.5.0.

AI Chat now better understands the General HTML Support configuration. The editor shares which additional HTML elements, classes, styles, and attributes are allowed in the content, so the AI produces replies that respect your content rules. Read more about how the AI adapts to your setup in the feature understanding guide.

We also made the Context Library available directly to users in the chat. Enable the new config.ai.chat.context.contextLibrary option to add the library to the “Add context” menu of AI Chat, where users attach a context to the conversation like any other resource. The list shows only the contexts the user token grants access to, and once the first message is sent, the context stays attached for the whole conversation. Learn more about offering contexts in the AI Chat picker.

AI-generated suggestions can already advertise their origin while they are open in the document. With this release, the same information can be surfaced in Revision History: revisions that include suggestions created with AI features can be visually marked as AI-assisted. Reviewers can tell at a glance which saved revisions involved AI, even after the suggestions were accepted.

The feature is opt-in and disabled by default. Enable it with the new config.revisionHistory.showAISource option. See the documentation for details.

We are making table column resizing more predictable. Columns no longer shrink by a few pixels when resizing starts while the editor content has a vertical scrollbar, and resizing the last column of a nested table by a resizer placed in a header cell no longer stretches that table to the full width of its parent table.

We also improved how table wrapper classes interact with the General HTML Support feature: the content-table and layout-table classes set on the <figure> element wrapping a content table are no longer preserved as arbitrary classes, keeping the output markup clean.

• ai: Introduced the DocumentCompare API, which captures a snapshot of the document, compares it with a processed version, and applies the resulting difference to the editor directly or as Track Changes suggestions.

• ai: Improved the AI agent’s understanding of the General HTML Support configuration. The agent now recognizes which additional HTML elements, classes, styles, and attributes are allowed in the content.

• ai: Changed AI Chat context items to match the behavior of file and link attachments. A context item can no longer be removed after the first message is sent, and its badge appears only next to that message.

• ai: Added a dedicated API method for attaching a Context Library item to the AI Chat context.

• revision-history: Added the config.revisionHistory.showAISource option for visually marking revisions that include changes created with AI features as AI-assisted, both in the revisions list and when comparing revisions.

• revision-history: Introduced the revisionHistory.showCommentHighlights configuration option for highlighting comment markers saved in revisions. This option is disabled by default.

  This option never highlights markers for removed or resolved comment threads because Revision History does not restore these comments automatically.

• collaboration-core, comments, track-changes: Fixed relative date labels such as “Today” and “Yesterday” to use calendar days instead of elapsed hours. An item created on the previous day is now labeled “Yesterday” regardless of how many hours have passed.
• collaboration-core, revision-history, track-changes: Fixed errors that occurred when opening the revision history viewer or using Track Changes data in integrations where AI features were registered on a context instead of an editor.
• ai: Improved error reports from AI features by including details from the point of failure. Previously, error tracking services did not receive these details.
• ai: Fixed an issue where AI Chat displayed outdated suggested changes while streaming a reply.
• collaboration-core: Fixed an issue where DocumentCompare produced inaccurate results when General HTML Support was configured to allow the data-id attribute.
• revision-history: Fixed an issue where RevisionTracker#saveRevision() modified the revision data object passed to it. Previously, reusing this object in multiple calls caused subsequent revisions to reuse the first revision’s identifier.
• revision-history: Fixed an issue where the revision viewer failed to open when the AI chat history feature was enabled.
• table: Fixed an issue where table columns shrank by a few pixels when resizing started while the editor content had a vertical scrollbar. Closes #20117.
• table: Fixed an issue where resizing the last column of a nested table using a resizer in a header cell stretched that table to the full width of its parent table.
• table: Fixed an issue where General HTML Support preserved the content-table and layout-table classes set on the <figure> element wrapping a content table as arbitrary classes.

• comments: Changed annotation activation for overlapping comments and suggestions to target the annotation displayed higher in the sidebar while keeping the other annotation accessible.

We are happy to announce the release of CKEditor 5 v48.4.0.

The new Context Library grounds CKEditor AI in your organization’s knowledge instead of generic instructions. A context is a named container managed on the AI service that holds reusable prompts and reference files, such as a style guide, a glossary, or compliance rules. Once attached, every AI Chat conversation, Quick Action, Review, and Translate run follows them.

Contexts can be applied environment-wide by an administrator, per editor instance via the new config.ai.defaultContext option, or per call in programmatic flows, and they stay invisible to the end user. Learn more in the documentation.

CKEditor AI now knows your editor better. AI Chat requests include a compact snapshot of the loaded features and their configuration, so the responses stay within what your editor supports and respect your configured values, like the allowed heading levels, font sizes, or color palettes. The result: AI changes that apply cleanly to your exact setup.

Feature understanding works out of the box, with no configuration required, and this is only the first iteration. Support for custom plugins, dynamic data features, and working with comments and suggestions is planned. See the documentation for details.

CKEditor AI now analyzes images embedded in the document, so it can describe them, generate captions, or take their contents into account when editing the surrounding text. It works in AI Chat and document processing. Learn more in the image analysis section of the integration guide.

The new config.trackChanges.clipboardMode option controls how Track Changes suggestions behave when content is copied or cut. The default 'keep' places the selected content on the clipboard as-is, while 'accept' resolves the suggestions in the copy, so the clipboard holds the final text, as if the suggestions were already accepted. The source document stays untouched, which makes this especially useful when pasting content outside the editor.

This release brings a set of upgrades to the Tables feature, focused on everyday editing:

• Split multiple cells at once: select several cells and split them all horizontally or vertically in one go, instead of repeating the action cell by cell.
• Horizontal scrolling for wide tables: tables wider than the editor now scroll horizontally instead of overflowing or squeezing the page layout, thanks to the new TableScroll plugin.
• Pixel-based column widths: the Column resize feature now supports widths in pixels, following the table width unit, and an exact column width can be set through the cell width field. Widths set via the resize handle and the properties form now stay in sync.

Inserting a block widget, such as an image or a table, no longer drops the active text formatting. The editor now carries selection attributes like bold, italic, or font styles over the widget, so typing after it (or inside a newly inserted table) picks up right where you left off.

• Added support for inline roots across the AI features, including AI Chat, Quick Actions, Review, and Translate.
• Programmatic AI actions now support multi-root editors and multi-editor Context setups, and processDocument() accepts new capabilities options that enable reasoning and web search.
• In multi-editor setups, AI Chat now re-uploads only the documents that changed, instead of every document on any change.
• The AI suggestion status indicators (Accepted, Rejected, Outdated) have a refreshed look, and the Outdated indicator now shows a reason-specific tooltip explaining why the suggestion became stale.
• AI interactions that modify content are now disabled when the target editor is read-only. In setups with multiple editors this is decided per editor, so interactions targeting editable editors stay available.
• Inline root corrections across features: Find and replace now finds matches inside inline roots, while Show blocks and Footnotes no longer incorrectly work with them.
• Link improvements: decorators can now be configured while creating a link, before it is inserted, and the “Link properties” button is no longer disabled for empty links when config.link.allowCreatingEmptyLinks is enabled.

• ai: Added support for multi-root editors and multi-editor Context setups to the AI Translate API (AITranslateGateway).
• ai: Added support for multi-root editors and multi-editor Context setups to the AI Review API (AIReviewGateway).
• ai: Added support for multi-root editors and multi-editor Context setups to AIDocumentProcessingGateway#processDocument(). Replaced the root option with roots and changed the return type from AIDocumentProcessingRunResult to AIRunResult<AIDocumentProcessingRunResult>.

• ai, collaboration-core: Added an optional root option to the Document Processing API’s processDocument() method, allowing integrators to target a specific root in multi-root editors and multi-editor Context setups.

• ai: Updated the appearance of the AI suggestion status indicators (Accepted, Rejected, and Outdated). Added a reason-specific tooltip to the Outdated indicator that explains why the suggestion became outdated.

• ai: Added optional capabilities to the AI Document Processing API’s processDocument() options, allowing callers to enable reasoning and web search for AI requests.

• ai: Added a snapshot of the editor’s loaded features and their configuration to AI Chat requests, allowing the agent to tailor its responses to the editor’s capabilities.

• ai: Added support for inline roots across the AI features, including AI Chat, Quick Actions, Review, and Translate.

• ai: Disabled content-modifying AI interactions, such as applying or inserting a suggestion, when the target editor is read-only. In setups with multiple editors, interactions targeting editable editors remain available.

• ai: Added a new configuration option, config.ai.extraHttpHeaders, allowing the AI service to analyze document images hosted behind authentication, for example from a private CDN.

• ai: Introduced the ai.defaultContext configuration option, allowing integrators to attach administrator-managed contexts from the Context Library, such as reusable prompts and reference files, to AI requests without exposing them in the user interface. This configuration is supported across all AI features, including AI Chat, AI Quick Actions, AI Review Mode, and AI Translate.

• link: Added support for configuring link decorators while creating a link, before inserting it into the document. Closes #20201.

• table: Added horizontal scrolling for tables wider than the editor, preventing them from overflowing or squeezing the page layout. This behavior is provided by the new TableScroll plugin.

• table: Preserved active text formatting, such as bold, italic, and font color, when inserting a table. Typing in any cell of the new table now continues the formatting used before the table. Closes #17152.

• table: Added support for column widths in pixels to the table column resize feature when the table uses pixel widths. The cell width field can now set an exact width for an entire column in a resized table. Closes #14236.

• table: Added support for splitting multiple table cells at once. Selecting several cells and choosing “Split cell vertically” or “Split cell horizontally” now splits each selected cell in one operation.

• track-changes: Added the trackChanges.clipboardMode configuration option to control whether suggestions are preserved or accepted when content is copied or cut. The source document remains unchanged.

  The default 'keep' mode places the selected content on the clipboard with its suggestions, while 'accept' places the final content as if the suggestions were accepted.

• widget: Preserved active text formatting when inserting a new paragraph after a block widget. The editor now copies selection attributes, such as bold, italic, and font styles, from the text preceding the widget. Closes #17152.

• ai: Fixed an editor crash that occurred when applying an AI Chat change in specific multi-level list scenarios.

• ai: Preserved comments and suggestions when applying an AI change to the surrounding content.

• ai: Disabled dragging and dropping files or URLs into the AI Chat panel while an AI response is being generated. Previously, dropped resources were uploaded and then discarded when the response finished or was interrupted.

• ai: Disabled the “Ask AI” quick action button while an AI Chat response is being processed, preventing a new chat interaction from starting before the current one finishes.

• ai: Fixed an editor crash that occurred for some AI Chat queries when General HTML Support was enabled and the content included an <h1> element.

• ai: Updated the AI Chat feed to scroll to every new error message.

• ai: Disabled AI Chat quick actions while a conversation is loading from history or a reply is streaming. Previously, they could be triggered before the chat was ready.

• ai: Fixed an issue where the AI Chat feed sometimes appeared stuck after submitting a message while a large document was loaded.

• ai: Fixed the AI Chat submit button remaining disabled after starting a new chat while a file or URL was still uploading in a previous conversation. Starting a new conversation now resets the upload progress state.

• ai: Fixed the formatBlock suggestion marker being cut off in AI suggestion previews, including the AI Chat feed.

• engine: Fixed a memory leak that occurred when an editor instance remained referenced after being destroyed.

• find-and-replace: Fixed an issue where Find and Replace did not find matches inside inline roots.

• find-and-replace: Fixed a memory leak that could degrade editor performance during long editing sessions after replacing all occurrences of a search phrase.

• footnotes: Prevented footnotes from being inserted into inline roots. Footnotes within inline roots now use the first non-inline root for the footnote definitions container instead of omitting it.

• fullscreen: Prevented contextual balloons from overlapping the main editor toolbar in fullscreen mode when scrolling through elements taller than the visible editor area, such as large tables. Closes #20194.

• link: Fixed the “Link properties” button being disabled for links with an empty URL, even when config.link.allowCreatingEmptyLinks was enabled.

• mention: Prevented the mention suggestions panel from overflowing the viewport on narrow screens. When the caret is close to the screen edge, the panel now shifts horizontally to keep the entire list visible. Closes #20182.

  Thanks to @ELHart05.

• show-blocks: Prevented Show Blocks from applying to inline roots. The toolbar button is now disabled when the editor has no block roots.

• style: Prevented style previews from overflowing their buttons in the Styles dropdown. Closes #20200.

• table: Fixed a crash (conversion-slot-filter-incomplete error) that occurred when loading or pasting content containing multiple <table> elements wrapped in a single aligning <div>. Closes #20209.

• ui: Fixed the contextual balloon closing unexpectedly when using its “Previous” and “Next” navigation buttons. Clicking these buttons no longer moves focus out of the editor, so focus-sensitive views such as the balloon toolbar stay visible.

• ai: Exposed structured backend error data from AI gateway connectors, such as an issues list describing fields that failed validation, under result.error.data.backendData.
• ai: Updated AI Chat in multi-editor setups to re-upload only changed documents. Previously, changing one document re-uploaded documents from all editors.
• document-outline: Added support for recognizing all heading elements (<h1> through <h6>) in Document Outline and Table of Contents, regardless of whether Heading or General HTML Support handles them. These elements now receive an id attribute in the document data and a headingId attribute in the model.
• Separated editor UI styles from content styles. No visual or functional changes are expected, but integrations with heavily customized styling should verify their appearance after updating.

We are happy to announce the release of CKEditor 5 v48.3.1.

The release addresses vulnerabilities identified in the protobuf.js package, used within our @ckeditor/ckeditor5-operations-compressor package for real-time collaboration.

Our analysis confirms that vulnerabilities do not affect CKEditor 5.

This release primarily aims to ensure that our customers using real-time collaboration features do not encounter unnecessary security alerts from their scanning tools. We are committed to maintaining the highest security standards, and this update reflects our ongoing efforts to safeguard user environments proactively.