Hi,
the "old_addr:*" tags are documented
https://wiki.openstreetmap.org/wiki/Key:old_addr:housenumber

The ones with a ":postal" suffix are not. If the addr:city:postal is required for sending post, they should be tagged on address nodes, not on the streets.

The proper tag for this should be discussed, involving the people working with addresses, e.g. from Nominatim.
