New features:

• #2444: Togglable toolbar buttons are now exposed as toggle buttons in the browser's accessibility tree.
• #4641: Added an option allowing to cancel the Delayed Editor Creation feature as a function handle for editor creators (CKEDITOR.replace, CKEDITOR.inline, CKEDITOR.appendTo).
• #4986: Added config.shiftLineBreaks allowing to preserve inline elements formatting when the shift+enter keystroke is used.
• #2445: Added config.applicationTitle configuration option allowing to customize or disable the editor's application region label. This option, combined with config.title, gives much better control over the editor's labels read by screen readers.

Fixed Issues:

• #4543: Fixed: Toolbar buttons toggle state is not correctly announced by screen readers lacking the information whether the feature is on or off.
• #4052: Fixed: Editor labels are read incorrectly by screen readers due to invalid editor control type for the Iframe Editing Area editors.
• #1904: Fixed: Screen readers are not announcing the read-only editor state.
• #4904: Fixed: Table cell selection and navigation with the tab key behavior is inconsistent after adding a new row.
• #3394: Fixed: Enhanced image plugin dialog is not supporting URL with query string parameters. Thanks to Simon Urli!
• #5049: Fixed: The editor fails in strict mode due to not following the use strict directives in a core editor module.
• #5095: Fixed: The clipboard plugin shows notification about unsupported file format when the file type is different than jpg, gif, png, not respecting supported types by the Upload Widget plugin.
• #4855: [iOS] Fixed: Focusing toolbar buttons with an enabled VoiceOver screen reader moves the browser focus into an editable area and interrupts button functionality.

API changes:

• #4641: The CKEDITOR.replace, CKEDITOR.inline, CKEDITOR.appendTo functions are now returning a handle function allowing to cancel the Delayed Editor Creation feature.
• #5095: Added the CKEDITOR.plugins.clipboard.addFileMatcher function allowing to define file formats supported by the clipboard plugin. Trying to paste unsupported files will result in a notification that a file cannot be dropped or pasted into the editor.
• #2445: Added config.applicationTitle alongside CKEDITOR.editor#applicationTitle to allow customizing editor's application region label.