Hi,
Some of vendors allow to users change SIM Card slot IMEI number via telnet/ssh connection. its not allowed on Yeastar TG series. customers keep asking about this feature. please consider.
Changing or allowing/supporting the change of an IMEI is illegal in many countries. Its purpose is to uniquely identify each device which includes many of the attributes/capabilities of the device to which the IMEI is assigned. It also forms the basis for many blocklists to prevent those device that have been stolen from being used.
There is no real valid reason to change the IMEI other than for uses that would be questionable at best or outright illegal.