System IVR 777 change number

[sip.bg]

I need to use number 777 as normal extension, as customer insists on. I can't change the extension number of system PIN protect IVR, i.e. 777 to something else. It was possible before version 14, but not anymore. Any glue ?

 

[sip.bg]

In version 15 is not possible to change system extension numbers like 700, 777, 888, 999.
In some cases customers may require to use these numbers as normal extensions for any reason.
Any glue ?