Old Avaya phone system - help please

I am doinf IT eemediation a nwe to me site.

They have a old Avaya phone system:

• IP 500 V2 vontrol unit

• 9600 series phones

All of the phoneas are on static IP adresses. We need to change them to DHCP

I had a dig through the Avaya online docs, but like most telecomm docs they are quite opaque.

Does anyone know how to reconfigur these phones, please?

Or do you know of any comms provider that still supports this old stuff that we could get in for a day? Location is Newbury, UK.