Comment 20 for bug 1901582

src/login/logind-seat-dbus.c: SD_BUS_PROPERTY("CanMultiSession", "b", property_get_const_true, 0, SD_BUS_VTABLE_PROPERTY_CONST|SD_BUS_VTABLE_HIDDEN),

So it does still exist, but it's hidden from introspection.
And always returns true anyway: 8f8cc84ba4612e74cd1e26898c6816e6e60fc4e9 which makes our check somewhat redundant!

I'm still confused by the reports in the duplicate saying it doesn't work.
It does here.

Can someone who still has an issue include output of:
 qdbus --system org.freedesktop.login1 /org/freedesktop/login1/seat/auto org.freedesktop.DBus.Properties.Get org.freedesktop.login1.Seat CanMultiSession

and reopen