Alcatel Deskphone 8008 SIP-Mode Auto Provisioning

[unlikely]

I hope this is the right forum for this question.

We have an Alcatel OXO system with a few analog phones and a few IP phones (8008). We've encountered many issues with the IP phones and the company managing the system, so we are considering switching to a different system. However, we would like to repurpose the IP phones to connect in SIP mode to the new system.

I understand it should be possible to auto-provision the 8008 by sending the address (or possibly the URL) of an HTTPS provisioning server via DHCP option 66.

On the status page of the web interface of a test 8008 phone, I can see:
Phone Model: 8008
Bootloader Version: 5.45.60
Software Version: 1.51.52
Time Zone: Europe/Paris
DM URL: https://provisioning.portal.mydomain.tld/

I assume I need to serve some files for each phone. These files could be generated by exporting the JSON configuration from the test phone and adapting it for other phones.

The issue is that I don't know how to name the files, and I can't see any access attempts to the provisioning web server from the phone while booting (from which I could have guessed the name of the file to serve).

Any ideas?

[unlikely]

Looks like was a firewall issue preventing the phone to access the web server.
Now I see they try to get a file named "/config.<macaddress_lowercase>.xml"
The issue now is that the format needed appear to be xml while from the management I can export a json so I have no clue of the syntax of this xml.

Any way to generate a template?

[unlikely]

Well I think I found some documentation on xml format, I tried, phone download the xml but apparently silently ignore and keeps its manually defined configuration.

No clue.