Cisco officially encourages using the (e.g., 8.x or 9.x) for current certifications. Version 5.3.3 is no longer directly supported by Cisco for official lab work but can sometimes be found in academic archives. Cisco Packet Tracer Resources - Cisco Networking Academy
However, if you are:
For instructors, it integrates with the Cisco NetSpace learning environment, enabling assignment distribution and automated grading. Cisco Packet Tracer 5.3 3 Download