Hi,
5320e/5330e/5340e are all backwards compatible, as below:
System Software Requirements
The Minimum System Software required to support the 5320e / 5330e / 5340e IP Phones:
• Mitel Communications Director (MCD), Release 5.0 SP2
• Mitel 5000 Communications Platform (CP) Release 5.1
• Mitel Border Gateway (Teleworker Solution) Release 7.1
• Mitel SX-200 IP Communications Platform (ICP) Release 5.0 (5330, 5340 only)
• Mitel HTML Toolkit Release 2.2
• SIP Release (TBD)
The 5320e, 5330e and 5340e operate as 5320, 5330 and 5340 Phones in Backwards Compatibility mode with the following System Software:
• Mitel Communications Director (MCD) Release 4.0 SP1
• Mitel 5000 CP Release 3.2
• Mitel Border Gateway (Teleworker) Release 5.2 SP1
• Mitel SX-200 ICP Release 4.0 UR3 (5330, 5340 Only)
• Mitel HTML Toolkit Release 2.0
Thanks