By DNS packet encoding, do you mean RFC 1101? Or something else?
At least 1035 ... but most implementations support more, we use this library so we support these rfcs https://github.com/balliegojr/simple-dns/blob/main/simple-dns/README.md#dns-packet-parserbuilder Pubky specifically cares about SVCB and HTTPs records in in RFC 9460 but the thing is, unsupported dns records are still parsed by anything that supports 1035... just not usefully.