As of about 1400 UTC Feb 4th, Visonic appear to have removed suppoirt for anything other than version 12.0 of their API. The excellent And3rsL/VisonicAlarm2 library relies on API version 8.0, which is no longer offered (and doesn’t work if you just “push on” and throw version 8 requests at it). Although there are multiple forks of the integration, they all use that library (or perhaps small derivations of it). So far as I am aware, there is no library for any API more recent than 8.0, nor is there any documentation, so a solution will involve a full reverse-engineering.
I doubt this is going to be a quick or easy thing to fix.