A subId is the only selector of a subscription's inbounds and external
links, so a blank one matched every client stored without a subId, as
clients embedded through inbounds/add or inbounds/import are. The
Telegram bot authorised a client by email and then looked its links up
by that blank subId, handing a bound user the working links of every
other subId-less client.
A blank subId now resolves to nothing in the subscription service, and
the bot builds a subId-less client's own links by email, as the panel's
client page does.
MHSanaei
duqigit