Migrating from TinyMCE 4 to TinyMCE 8

Overview

TinyMCE has evolved significantly from version 4 to version 8.0, introducing major architectural changes, modern UI improvements, enhanced performance, and better security. This comprehensive guide outlines the critical breaking changes, recommended migration action steps, and top-level configuration adjustments required to upgrade from TinyMCE v4 to v8.0.

This guide provides a complete migration path from TinyMCE 4 to TinyMCE 8, covering all changes across versions 5, 6, 7, and 8 in a single comprehensive document.

Key Changes

UI Themes and Skins

  • Removed: modern, lightgray, and mobile themes/skins.

  • New: silver theme with oxide skin (supports light and dark variants). see customize-ui.

  • Impact: Custom v4 skins/themes are incompatible with v8.0 and must be rewritten using the oxide skin structure.

Example:
tinymce.init({
  selector: "textarea",
  skin: "oxide-dark",
  content_css: "dark",
});

Plugin Ecosystem

The TinyMCE plugin ecosystem was significantly restructured across versions 5, 6, and 7, with several plugins being removed, folded into the TinyMCE core, or reclassified as premium features. The following breakdown clarifies the status of each affected plugin.

  • Removed Plugins (no longer available as of TinyMCE 6.0):

    • bbcode, fullpage, legacyoutput: Deprecated in 5.9.0. Removed in 6.0.

    • imagetools: Removed in 6.0. Replaced by the premium Enhanced Image Editing feature, available via the editimage plugin introduced in TinyMCE 6.0.

    • textcolor: Removed in 6.0. Use the premium Color Picker plugin instead.

  • Integrated into TinyMCE core:

    • paste, hr, noneditable, table, print, colorpicker and contextmenu: These plugins were absorbed into TinyMCE core and no longer require separate installation. See Copy and Paste, Non-editable Content, Table, and Context Menu for more information.

    • contextmenu: Deprecated in version 5.0 following the integration of context menu functionality into TinyMCE core editor. Removed in version 6.0. For more information, see the contextmenu documentation.

    • tabfocus: Removed in 6.0. Keyboard navigation via Tab is now handled by the browser and TinyMCE core.

  • Now Premium Only:

    • mediaembed, tableofcontents: These features are available through premium plugins. See Media Embed and Table of Contents for more information.

    • spellchecker: Deprecated in 5.9.0. Removed in 6.0.

      • Use browser_spellcheck: true or the premium Spell Checker plugin.

    • advtemplate: Replaces the template plugin for advanced templating use cases.

    • template: Removed in 7.0. Replaced by the premium Templates plugin.

Plugin Migration Tips

  • contextmenu (removed in v6):

  • bbcode (removed in v6):

    • Implement custom parsing or server-side processing if BBCode support is required.

  • fullpage (removed in v6):

    • Use custom templates or server-side logic to handle full HTML documents.

  • template (removed in v7):

    • Use the premium advtemplate plugin or implement custom modal dialogs.

  • textcolor (removed in v6):

    • Use the forecolor and backcolor toolbar buttons for text color functionality.

  • imagetools: (removed in v6):

Toolbar and Menu name changes

If you used the following toolbar buttons or menu options, they have changed names across major TinyMCE versions. Please refer to the release notes for each version for complete migration details.

TinyMCE 5 → TinyMCE 6:

  • formatselect → blocks (toolbar item)

  • blockformats → blocks (menu item)

  • styleselect → styles (toolbar item)

  • formats → styles (menu item)

  • fontselect → fontfamily (toolbar item)

  • fontformats → fontfamily (menu item)

  • fontsizeselect → fontsize (toolbar item)

  • fontsizes → fontsize (menu item)

  • imagetools → editimage (plugin and related toolbar items)

  • toc → tableofcontents (plugin, menu item, and toolbar item)

  • tocupdate → tableofcontentsupdate (toolbar item)

TinyMCE 6 → TinyMCE 7:

  • InsertOrderedList and InsertUnorderedList commands were removed from TinyMCE core and are now provided by the Lists plugin.

  • Default text pattern triggers were updated to activate on Space instead of Enter. A trigger property was added to configure block-level text pattern behavior.

TinyMCE 7 → TinyMCE 8:

  • Several API methods have been deprecated or removed (see the API Changes section below for details)

  • License key system has been updated with new format requirements

  • DOMPurify sanitization has been strengthened

Refer to the latest release notes at latest release notes for further details.

Always refer to the latest plugin documentation at plugins for up-to-date availability and migration guidance.
Example of Toolbar Changes:
tinymce.init({
  selector: "textarea",
  toolbar: "undo redo | forecolor backcolor | bold italic | alignleft aligncenter alignright alignjustify",
  plugins: ["lists link image table code"]
});

Content Structure

  • Removed: forced_root_block: false.

    • Requirement: All editor content must be enclosed in block elements (e.g., <p>).

Example:
tinymce.init({
  selector: "textarea",
  forced_root_block: "p"
});

Configuration Changes

  • Removed in TinyMCE 6.0: Legacy mobile theme was removed, but mobile-specific configuration is still supported through the mobile option.

  • Default Changes in TinyMCE 7.0:

  • New Options in TinyMCE 7.0:

  • New Options in TinyMCE 8.0:

    • Enhanced license key system with new format requirements

    • Stricter DOMPurify sanitization with SAFE_FOR_XML enabled by default

    • New crossorigin configuration option for cross-origin resource loading

Example:
tinymce.init({
  selector: "textarea",
  toolbar: "undo redo | blocks | bold italic | alignleft aligncenter alignright alignjustify | outdent indent | removeformat",
  toolbar_mode: "floating",
  // Required in TinyMCE 8.0 if self-hosting
  license_key: "T8LK:...", // New format required
  // Security options now enabled by default in TinyMCE 7.0
  sandbox_iframes: true,
  convert_unsafe_embeds: true,
  // Optional: exclude specific domains from iframe sandboxing
  sandbox_iframes_exclusions: ["youtube.com", "vimeo.com"],
  // Accessibility improvement, now enabled by default
  highlight_on_focus: true,
  // New in TinyMCE 8.0: Cross-origin resource loading
  crossorigin: (url, resourceType) => 'anonymous'
});

Licensing Changes (GPL v2+ and Commercial)

  • Legacy License: TinyMCE 4 was licensed under LGPL 2.1.

  • New License: TinyMCE 8.0 is licensed under GPL v2+ or a commercial license.

  • Impact: The License key option is required as part of your editor configuration if self-hosting TinyMCE. This requirement does not apply if you are loading TinyMCE from the cloud.

License Key System Update in TinyMCE 8

TinyMCE 8 introduces a new license key system that requires immediate attention:

  • New Format: License keys now use the prefix T8LK: for commercial licenses or GPL+T8LK: for GPL with Premium Features

  • Mandatory Requirement: Self-hosted deployments now require a valid license key; without one, the editor will be set to readonly

  • License Key Manager: Self-hosted commercial deployments require the new License Key Manager addon

For complete details, see License Key System Update in the 7→8 migration guide.
Example:
tinymce.init({
  selector: "textarea",
  license_key: "T8LK:your-license-key" // New format required
});

API Changes

Several API methods have been deprecated or removed across versions 5-8. Key changes include:

Deprecated in TinyMCE 8

editor.selection.setContent

The editor.selection.setContent API has been deprecated and will be removed in TinyMCE 9.

Impact: This change simplifies content manipulation by consolidating insertion methods.

Migration steps:

To replace editor.selection.setContent, use editor.insertContent instead. The new method is more consistent with other content manipulation methods in TinyMCE.

Example Usage
// Deprecated in TinyMCE 8, will be removed in 9
editor.selection.setContent('<p>New content</p>');

// Recommended replacement
editor.insertContent('<p>New content</p>');
fire() method

The fire() method has been replaced by dispatch() for event handling. The fire() method will be removed in TinyMCE 9 to avoid confusion with its name.

// Deprecated in TinyMCE 8, will be removed in 9
// Old approach for dispatching custom events
editor.fire('someEvent');

// New approach for dispatching custom events
editor.dispatch('someEvent');
editor.documentBaseUrl

The undocumented editor.documentBaseUrl property has been removed.

Example Usage
// Removed in TinyMCE 8
console.log('documentBaseUrl', editor.documentBaseUrl);

// Use this instead
console.log('documentBaseURI', editor.documentBaseURI.getURI());
Use editor.documentBaseURI.getURI() for all base URL operations.
skipFocus and skip_focus Consolidation (v8)

The skipFocus and skip_focus options for the ToggleToolbarDrawer command have been consolidated into a single, more consistent argument in TinyMCE 8.0.

Impact:

  • Reduces API complexity

  • Clarifies intended behavior

  • Requires updating command calls

Migration Steps:

  1. Locate all instances of ToggleToolbarDrawer command usage

  2. Replace skip_focus with skipFocus in command parameters

  3. Test toolbar drawer behavior

Example:
// Old TinyMCE 7 usage
editor.execCommand('ToggleToolbarDrawer', false, null, { skip_focus: true });

// New TinyMCE 8 usage
editor.execCommand('ToggleToolbarDrawer', false, { skipFocus: true });

Removed Methods

Legacy API Methods (removed in v6)

  • editor.addButton, editor.addMenuItem, editor.windowManager.open (replaced by editor.ui.registry.* API)

Autocompleter ch property (removed in v7)

The ch configuration property was removed in TinyMCE 7.0. Use the trigger property instead.

// Old approach (removed in v7)
editor.ui.registry.addAutocompleter('myAutocompleter', {
  ch: '@',
  // ... other options
});

// New approach
editor.ui.registry.addAutocompleter('myAutocompleter', {
  trigger: '@',
  // ... other options
});
remove_trailing_brs property (removed in v7)

The remove_trailing_brs setting was removed from the DomParser API in TinyMCE 7.0, after being deprecated in TinyMCE 6.5.

Text Pattern Changes (v7)

TinyMCE 7.0 updated the default behavior of text_patterns to apply formats when the user presses the Space key instead of Enter.

Impact:

  • Markdown-style formatting now triggers on Space key press

  • Previous Enter key behavior can be restored by configuring trigger: 'enter'

  • This affects all text patterns including headings, lists, blockquotes, and horizontal rules

Migration Steps:

  1. Test existing text pattern behavior

  2. Update configurations if Enter key triggering is required

  3. Review user experience with new Space key triggering

  4. Consider updating user documentation about text pattern behavior

Example:
// Default TinyMCE 7+ behavior (Space key trigger)
tinymce.init({
  selector: "textarea",
  text_patterns: [
    { start: '#', format: 'h1', trigger: 'space' },
    { start: '##', format: 'h2', trigger: 'space' },
    { start: '1.', cmd: 'InsertOrderedList', trigger: 'space' },
    { start: '*', cmd: 'InsertUnorderedList', trigger: 'space' },
    { start: '>', cmd: 'mceBlockQuote', trigger: 'space' }
  ]
});

// Restore previous behavior (Enter key trigger)
tinymce.init({
  selector: "textarea",
  text_patterns: [
    { start: '#', format: 'h1', trigger: 'enter' },
    { start: '##', format: 'h2', trigger: 'enter' },
    { start: '1.', cmd: 'InsertOrderedList', trigger: 'enter' },
    { start: '*', cmd: 'InsertUnorderedList', trigger: 'enter' },
    { start: '>', cmd: 'mceBlockQuote', trigger: 'enter' }
  ]
});
Autocompleter Configuration Changes (v7)

The ch configuration property for autocompleters has been removed. Use the trigger property instead.

Migration Steps:

  1. Replace ch: '<string>' with trigger: '<string>' in autocompleter configurations

  2. Test autocompleter functionality

  3. Update any custom autocompleter implementations

Example:
// Old TinyMCE 6 configuration
editor.ui.registry.addAutocompleter('myautocompleter', {
  ch: '@',
  minChars: 2,
  fetch: function(pattern) {
    return Promise.resolve(['item1', 'item2']);
  }
});

// New TinyMCE 7+ configuration
editor.ui.registry.addAutocompleter('myautocompleter', {
  trigger: '@',
  minChars: 2,
  fetch: function(pattern) {
    return Promise.resolve(['item1', 'item2']);
  }
});
force_hex_color option (removed in v7)

The force_hex_color option has been removed. Only RGB values in absolute format like rgb(255, 255, 255) are now converted to HEX values.

Text Pattern Changes (v7)

TinyMCE 7.0 updated the default behavior of text_patterns to apply formats when the user presses the Space key instead of Enter.

Impact:

  • Markdown-style formatting now triggers on Space key press

  • Previous Enter key behavior can be restored by configuring trigger: 'enter'

  • This affects all text patterns including headings, lists, blockquotes, and horizontal rules

Migration Steps:

  1. Test existing text pattern behavior

  2. Update configurations if Enter key triggering is required

  3. Review user experience with new Space key triggering

  4. Consider updating user documentation about text pattern behavior

Example:
// Default TinyMCE 7+ behavior (Space key trigger)
tinymce.init({
  selector: "textarea",
  text_patterns: [
    { start: '#', format: 'h1', trigger: 'space' },
    { start: '##', format: 'h2', trigger: 'space' },
    { start: '1.', cmd: 'InsertOrderedList', trigger: 'space' },
    { start: '*', cmd: 'InsertUnorderedList', trigger: 'space' },
    { start: '>', cmd: 'mceBlockQuote', trigger: 'space' }
  ]
});

// Restore previous behavior (Enter key trigger)
tinymce.init({
  selector: "textarea",
  text_patterns: [
    { start: '#', format: 'h1', trigger: 'enter' },
    { start: '##', format: 'h2', trigger: 'enter' },
    { start: '1.', cmd: 'InsertOrderedList', trigger: 'enter' },
    { start: '*', cmd: 'InsertUnorderedList', trigger: 'enter' },
    { start: '>', cmd: 'mceBlockQuote', trigger: 'enter' }
  ]
});

The table_responsive_width option has been replaced by table_sizing_mode in TinyMCE 7.0.

Migration Steps:

  1. Replace table_responsive_width with table_sizing_mode in your configuration

  2. Update the option value to match the new API

  3. Test table responsive behavior

Example:
// Old TinyMCE 6 configuration
tinymce.init({
  selector: "textarea",
  table_responsive_width: true
});

// New TinyMCE 7+ configuration
tinymce.init({
  selector: "textarea",
  table_sizing_mode: "responsive"
});

For complete API migration details, see Core API Changes in the 7→8 migration guide.

Plugin Changes

Template Plugin Removal (v7)

The open-source Template plugin and associated config options have been removed in TinyMCE 7.0.

Customers using the template plugin are recommended to upgrade to the premium Templates plugin which provides enhanced template functionality. For more information on the Templates plugin, see: Templates for more details.

Removed Template options:

  • template_cdate_classes

  • template_cdate_format

  • template_mdate_classes

  • template_mdate_format

  • template_replace_values

  • template_preview_replace_values

  • template_selected_content_classes

Media URL Resolver Changes (v7)

In TinyMCE 6 and earlier, the media_url_resolver option provided resolve and reject callbacks, rather than a Promise. In TinyMCE 7, the media_url_resolver option now requires a Promise to be returned.

Old expected value implementing callbacks
tinymce.init({
  selector: 'textarea',
  plugins: 'media',
  toolbar: 'media',
  media_url_resolver: (data, resolve, reject) => {
    if (data.url.indexOf('YOUR_SPECIAL_VIDEO_URL') !== -1) {
      const embedHtml = `<iframe src="${data.url}" width="400" height="400" ></iframe>`;
      resolve({ html: embedHtml });
    } else {
      resolve({ html: '' });
    }
  }
});
New expected value returning a Promise
tinymce.init({
  selector: 'textarea',
  plugins: 'media',
  toolbar: 'media',
  media_url_resolver: (data) => {
    return new Promise((resolve) => {
      if (data.url.indexOf('YOUR_SPECIAL_VIDEO_URL') !== -1) {
        const embedHtml = `<iframe src="${data.url}" width="400" height="400" ></iframe>`;
        resolve({ html: embedHtml });
      } else {
        resolve({ html: '' });
      }
    });
  }
});

UI and UX Changes

Table Height Changes (v7)

Previously, TinyMCE added numerous height styles when resizing table rows such as on the table element, tr elements, and td elements. This resulted in unnecessarily verbose HTML output.

TinyMCE 7.0 addresses this by making a couple of changes:

  • The height input field has been removed from the "Cell Properties" dialog. Now, the "Row Properties" dialog is the only way to update row heights.

  • When a table is resized using the resize handles or the "Row properties" dialog, existing height styles will be stripped from td/th elements where applicable and only applied to the table element and tr elements.

TinyMCE 7.0 does not provide any fallback to revert to the old behavior.

Notification Close Button (v7)

In previous versions of TinyMCE, notifications were able to be displayed without a close button (X). Accessibility is an important component of the editor, and when this button is not in a notification, that notification cannot be closed via keyboard navigation.

As of TinyMCE 7.0, the closeButton property has been removed from the notification API, with all notifications now displaying a visible closeButton. This is to allow notifications to be closed using the Tab key.

Split Button Changes (v8)

TinyMCE 8.0, split toolbar buttons now render as two distinct components: one for the primary action and one for the dropdown chevron.

This structural change modifies the DOM layout of split buttons and may break custom CSS rules that rely on the previous structure.

Impact: This change only affects integrators using custom skins.

Migration Guide:

If your implementation includes a custom skin, follow these steps to ensure compatibility:

  • Confirm whether your project uses a custom skin.

  • Rebuild your custom skin using the TinyMCE 8.0 codebase. See Creating a Skin for instructions.

  • Update your split button usage to align with the new structure, including support for the chevronTooltip option. Refer to Split Toolbar Buttons for updated configuration details.

  • Test the rendering and interaction of split buttons in your editor to verify expected behavior.

Security Changes

Sandbox Iframes (v7)

In TinyMCE 6.8.1, the sandbox iframes editor option was introduced to allow iframes to be sandboxed by default when inserted into the editor.

In TinyMCE 7.0, the default for sandbox_iframes will change from false to true, meaning that all iframe elements inserted into the editor will be given the sandbox="" attribute by default, preventing most actions, including scripting and same-origin access, which may break existing editor content or produce undesirable effects.

To prevent any expected iframes from being sandboxed, we recommend adding the source domains of such iframes to the new sandbox_iframes_exclusions option list, and including the domains in the default list where necessary. To prevent all iframes from being sandboxed, set the option sandbox_iframes to false in your editor configuration.

Convert Unsafe Embeds (v7)

In TinyMCE 6.8.1, convert_unsafe_embeds editor option was introduced to allow object and embed elements to be converted by default to the correct element, respective of the MIME type, automatically when inserted into the editor.

In TinyMCE 7.0, the default value for convert_unsafe_embeds will change from false to true, meaning that all object and embed tags will automatically be converted to different elements when inserted to the editor.

Example of before/after conversion.
<!-- Before Conversion -->
<object type="video/mp4" data="https://sneak-preview.tiny.cloud/3adc27b5-bb2f-49f0-9ccc-72b7c48313b0/bad.mov"></object>

<!-- After Conversion -->
<video src="https://sneak-preview.tiny.cloud/3adc27b5-bb2f-49f0-9ccc-72b7c48313b0/bad.mov" controls="controls"></video>

DOMPurify Update (v8)

TinyMCE 8.0 updates the DOMPurify dependency to version 3.2.6 and enables the SAFE_FOR_XML flag by default. This is a breaking change: content that previously passed sanitization in TinyMCE 7 may now be stripped or altered during the sanitization process.

This change improves security and aligns with DOMPurify’s recommended defaults. However, existing content and integrations that relied on the previous, less strict sanitization behavior may be impacted.

Key Changes:

  • DOMPurify upgraded to 3.2.6

  • SAFE_FOR_XML enabled — This setting enforces stricter handling of comments and attribute values, preventing certain XSS vectors.

  • Content Impact — HTML comments containing tags, Internet Explorer conditional comments, and attributes with HTML-like values may now be removed during sanitization. Content that was previously allowed may be stripped.

Migration Steps:

  • Review workflows and test content that previously relied on relaxed sanitization.

  • TinyMCE now provides the Content Filtering: allow_html_in_comments option option. Enabling this option allows HTML tags in comments with sanitization still enabled.

Using allow_html_in_comments increases the risk of XSS vulnerabilities. allow_html_in_comments is not recommended for production use unless you fully understand the implications and have appropriate security measures in place.

Service Changes

Java Swing Integration Deprecation (v8)

TinyMCE’s Java Swing integration has been deprecated in TinyMCE 8.0 and will reach end-of-life as of December 31, 2025.

Impact: Customers using the Java Swing integration need to plan for migration to alternative solutions before the end-of-life date.

Migration checklist:

  • Evaluate alternative integration options

  • Plan migration timeline to complete before December 31, 2025

Transition from Java WAR Files to Containerized Services (v8)

TinyMCE 8.0 no longer includes Java WAR files for backend services like the spell checker. Customers are required to migrate to modern Docker/OCI containers for self-hosted deployments.

Impact: This reduces infrastructure complexity and aligns with modern DevOps practices.

Migration checklist:

  • Inventory current WAR file deployments

  • Review containerization requirements for your environment

  • Plan transition timeline to containerized services

  • Set up container infrastructure (Docker/Kubernetes)

  • Deploy and test containerized services

  • Update service connection configurations

  • Contact Tiny Support if legacy WAR files are still needed

Migration Tips

  1. Backup and Prepare: Ensure comprehensive backups before upgrading.

  2. Update Core Initialization:

    1. Update theme, skin, and to reflect the new oxide theme and skin.

      1. In TinyMCE 4, there were multiple themes available including 'modern', 'inlite', and 'mobile'. These themes were removed in TinyMCE 5 and combined into a single responsive theme called "Silver".

    2. Update forced_root_block: false options to forced_root_block: "p".

    3. Consolidate toolbars.

    4. Review new v8.0 defaults for security settings.

    5. Update license key to new format if self-hosting.

  3. Plugin Migration:

    1. Remove deprecated plugins from your configuration.

    2. Update renamed plugins (e.g., spellchecker → tinymcespellchecker).

    3. Verify premium plugins for compatibility.

    4. Install License Key Manager addon if using commercial license.

  4. Custom Code Updates:

    1. Rewrite custom plugins using the editor.ui.registry.* API. see editor.ui.registry.

    2. Replace v4 API methods like editor.addButton, editor.addMenuItem, editor.windowManager.open.

    3. Update media embed handling (media_url_resolver API changes). see media_url_resolver.

    4. Replace deprecated API methods (editor.selection.setContent, editor.fire(), etc.).

  5. CSS Updates:

    1. Update custom styles to align with the new Oxide standard. While many .mce-* classes have been replaced with .tox-* classes, some .mce-* prefixes remain in use. Review your CSS to ensure compatibility.

    2. Update split button CSS if using custom skins (TinyMCE 8 change).

  6. Testing and Deployment:

    1. Thoroughly test your updated configuration before production deployment.

    2. Validate media, iframe, and content security settings.

    3. Test license key functionality and premium features.

    4. Verify DOMPurify sanitization behavior with your content.

Additional Resources

To make your upgrade smooth, check the following version-specific migration guides:

These include deeper configuration notes, plugin replacements, and examples.

Next Steps

Ensure you follow the migration steps carefully to avoid common issues like missing plugins, broken UI, and unexpected formatting changes. Consider running your updated editor in a staging environment for a complete verification before final deployment.

Migration Checklist

Before deploying to production, verify:

  • License key is updated to new format (T8LK: prefix)

  • License Key Manager addon is installed (commercial licenses)

  • All deprecated API methods have been replaced (editor.selection.setContent, editor.fire(), etc.)

  • Custom skins have been rebuilt for TinyMCE 8 compatibility

  • DOMPurify sanitization behavior is tested with your content

  • Cross-origin resource loading is configured if needed

  • All premium features are working correctly

  • Media URL resolver has been updated to use Promises

  • Autocompleter configuration uses trigger instead of ch

  • Template plugin has been replaced with premium Templates plugin if needed

  • Language pack files are updated to RFC5646 format

  • Accessibility checker configurations are updated for W3C standards

  • Empty file references are removed from build processes

  • Java Swing integration migration is planned (if applicable)

  • Medical English dictionary references are removed

  • WAR file deployments are migrated to containerized services

  • Split button CSS is updated for custom skins

  • Table height handling is tested

  • Notification close button behavior is verified

  • Sandbox iframes configuration is reviewed

  • Convert unsafe embeds behavior is tested