The RPC document splits a store tier change by store and direction: the
app never starts one, an App Store raise seen within a day of its charge
is sent as upgradeBadgeSubscription, every other change waits for the
renewal check, and a Play plan change is a new token, a new purchase.
transferBadge and its limits are checked against the handlers, and the
upgrades that are not built are marked so.
The overview admits what Restore discloses: the service links the two
purchase keys, a store receipt moves its subscription to whoever presents
it within the move limit, and a new badge or tier is shown as soon as it
is issued. The Android gap names what remains of Restore.