On Wed, Mar 11, 2015 at 6:14 PM, Mike Hearn <mike@plan99.net> wrote:
  • Electrum v2 with a version number but no date
  • myTREZOR with no version and no date and BIP44 key derivation. Some seeds I believe are now being generated with 24 words instead of 12.
  • MultiBit HD with no version and a date in a custom form that creates non-date-like codes you are expected to write down. I think BIP32 and BIP44 are both supported (sorta).
  • GreenAddress with no version, no date and BIP32
  • Other bitcoinj based wallets, with no version and a date written down in normal human form, BIP32 only.
To my knowledge, myTREZOR, Multibit HD and GreenAddress uses BIP39, just different scheme for key derivation (myTREZOR uses full BIP44, Multibit HD uses BIP44 with first account only and GreenAddress uses another scheme because it's multisig only wallet).

I disagree with the need of some version "magic flags" or creation date stored in the mnemnonic, for those reasons:

a) If we fail in the way how mnemonic algo is defined, then some magic, extra version flag won't save our asses, because we'll fail in meaning of its meaning. Then it will be completely useless, as implementations cannot rely on it. I know Thomas was sound proponent of this solution, but he was unable to give any reasonable rules about who/how define meaning of version flag.

b) "Creation date" is just a short-term hack. Considering that mnemonic words are kind of cold storage (longterm storage), it *really* does not make much difference in 2020, if your wallet has been created in 02/2014 or 10/2016. If there's performance issue with scanning of the blockchain, creation date don't save our asses. We need to find another solution, and as a bonus, we don't need users to know some weird numbers on top of mnemonic itself.

> From my interpretation of BIP39, wordlists DO NOT REQUIRE to be fixed between wallet providers. There is some recommendations regarding the wordlists to help with things such as predictive text, so mobile apps can easily predict the word being typed in after a few chars etc.

Exactly! After some community feedback, we changed BIP39 algo to be one-way only, which means you can use *any* wordlist to create the mnemonic, and any other implementation can derive BIP32 root node even without knowing that particular wordlist. Namely this has been changed because of constructive criticism of ThomasV, and from discussion on the mailing list I had a feeling that we've found a consensus. I was *very* surprised that Electrum 2.0 started to use yet another algo "just because".

Shortly said, I think BIP39 does perfect job and there's no need to use anything else.

Cheers,
Marek