CKEditor editing. A custom collaborative solution can be build by using the CKEditor 5 Framework components and real-time collaborative editing can be enabled by connecting to the CKEditor Cloud Services. A ready to use, drop-in component based on CKEditor 5 (Letters) offers a complete solution for real-time collaborative writing. CKEditor 4 is fully compatible with most internet browsers, including latest stable releases from Google Chrome, Firefox, Safari, Microsoft Edge, Opera and Internet Explorer 10 and 11. In mobile environments, it has close to full support in Safari (iOS6 +) and Chrome(Android) CKEditor 5 is also compatible with Google Chrome, Firefox, Safari,
WebSocket in Firefox 6, Safari 6, Google Chrome 14, Opera 12.10 and Internet Explorer 10. A detailed protocol test suite report lists the conformance of those browsers to specific protocol aspects. An older, less secure version of the protocol was implemented in Opera 11 and Safari 5, as well as the mobile version of Safari in iOS 4.2. The BlackBerry Browser in OS7 implements WebSockets. Because of vulnerabilities, it was disabled in Firefox 4 and 5, and Opera 11. To establish a WebSocket connection, the client sends a WebSocket handshake request, for which the server returns a WebSocket handshake response, as