What's new in Cisco Packet Tracer 7.3 ?
Packet Tracer 7.3 main new feature is the support of the CCNA 7 package which is not compatible with previous Packet Tracer versions. For CCNA 6 (and older versions), Cisco recommends instructors and students to stay with Packet Tracer 7.2.2. Students learning both CCNA 6 and 7 should use Packet Tracer 7.3.0.

Packet Tracer 7.3 workspace improvements :

• New workspace themes
• Aligned workspace objects
• Ability to deploy network devices to a specific rack
• Accessibility update
• Ability to name a physical rack

Protocol and software improvements :

• IP OSPF Point-to-Point on Ethernet interface
• IPv6 OSPF Point-to-Point on Ethernet interface
• Dynamic ARP inspection
• WLC GUI fixes and enhancements
• DHCP snooping fixes and enhancements
• Section output modifier for show commands
• Accessibility, security, and usability enhancements and optimizations for all platforms
• Upgraded PTSA and PTMO support
• Various enhancements to existing protocols

New devices in Packet Tracer 7.3 :

• Cisco 4331 Integrated Services Router
• Cisco Wireless Lan Controller 3504