Bip39 History. From this issue ahead the seed might be composed on paper or spoken more than phone which opened up new, physical means of backing up the seed (several paper copies in various spots, sturdy copies on metal plates with further protection from fireplace/flood and so on.). The BIP39 https://troymwhsb.mysticwiki.com/1101348/the_anatomy_of_a_bip39_phrase_entropy_words_and_stability