Please note that CKEditor 4 reached its End of Life (EOL) in June 2023. From then on, it receives no more updates, new features, bug fixes, and most importantly, security patches.
If you have an active CKEditor 4 subscription and need help, you can contact our support team. If you are not ready to migrate yet, for a limited time we are offering a paid Extended Support Model that will protect you against security vulnerabilities and/or breaking third-party API changes.
CKEditor 5 is a new concept of rich text editor. Compared to CKEditor 4, every aspect of it has been redesigned - from installation, to integration, to features, to its data model and its API. Therefore, moving applications from CKEditor 4 to CKEditor 5 means migration rather than an upgrade. Please see the article about migration to better understand how to migrate to CKEditor 5.