There is a tftp provisioning server with 4.0.4 software for polycom Sound Station IP 5000.
The phones get tftp address from dhcp option. I upgraded one phone to version 4.0.11 but if the phone is rebooted then software is downgraded to to version 4.0.4
I can't find any option in the phone configuration file to forbid the software downgrade.
Is there any possibility to disable upgrading/downgrading of software for telephone while provisioning?