We are sorry to inform you that CKEditor 5 does not support Internet Explorer 11 yet.
Don't worry - we have it on our roadmap.Browser compatibility section
Real-time collaborative editing
Write collaboratively and edit the same documents simultaneously with other online users. See the connected users and what they are currently editing in the document thanks to real-time cursor and selection synchronization.
Integrate your content review process with the rich text editor. Select any piece of content and comment on it. Add a comment to block elements such as embedded media or images.
Use comment-only mode to offer a convenient way of adding and tracking feedback.
Track typing, deletions, splitting or merging blocks.
Track formatting or styling changes (coming soon).
Track inserting widgets, tables, images, media or any other block content.
Comment on suggested changes (coming soon).
Suggest, approve or reject changes.
Show suggestions or the final document (coming soon).