Settings > Security & sessions still had the full enrolment flow --
QR code, secret, "Set up" -- for something that cannot be signed in
with. Turning 2FA on there took a working account and made webmail
unreachable from any device not already signed in, because ihasmail
has nowhere to send a TOTP code: Stalwart accepts one through an
OAuth flow alone and offers no password grant (#75). The one mercy
was that enabling reseals the current session onto a fresh app
password, so the browser doing it stayed in -- and the next sign-in
elsewhere did not.
So the enrolment path is gone until sign-in with a code works.
Turning 2FA *off* stays. It is a plain registry write, it was
verified live on 0.16.19, and anyone already enrolled -- here or in
Stalwart's own settings -- needs a way back. That control is now the
whole section, and it appears only for an account that has 2FA on;
everyone else no longer sees the heading at all.
The password form keeps its authenticator-code field on the same
condition, since Stalwart demands a code on every credential write
once 2FA is on.
Nothing changes on the server: /api/account/2fa/begin and /enable
are untouched and still tested, ready for the OAuth work that makes
them usable. The sign-in page's code field is also untouched -- it
already explains itself and points at app passwords.
README no longer advertises enrolment by QR code, and the roadmap
entry says which direction the setting still moves.