[flurdy]

>> - when receiving a new card due to upgrade the old one becomes void but there's no mention anywhere of this

> - Sounds reasonable?

Experience shows that postal deliveries might be really slow, so no guarantee when it arrives. Some deliveries just gets lost or stolen. Some people are travelling and not physically near their postal address for awhile. A lot of students and long-distance commuters really have two places they live so might not be staying very often where the card gets delivered. A lot of people (me) just don't open letters straight away, and certainly don't put the new card in my wallet straight away.

Which is why established banks know you need a month or so overlap. And modern banks know how to notify the customer properly that a new card is available. And progressive banks know to only deactivate the old card once the new one has been used.