Currently, if push was enabled for an account (it's global currently) it's not possible to remove the account if it's disabled or can't connect to the server (so it's not possible to disable push for that account via XMPP).
The idea is to offer REST API on push.tigase.im to which Siskin make a request deregistering the device.
Andrzej Wójcik (Tigase) commented 3 years ago
We already have that but, as explained in #servers-352, the configuration was broken. As we are not sure if with EBS we can "rewrite" HTTPS requests, I'll update SiskinIM to support unregistration even without rewrite (fallback).
Currently, if push was enabled for an account (it's global currently) it's not possible to remove the account if it's disabled or can't connect to the server (so it's not possible to disable push for that account via XMPP).
The idea is to offer REST API on push.tigase.im to which Siskin make a request deregistering the device.