On Sat, May 14, 2016 at 7:08 AM, Pavol Rusnak via bitcoin-dev <bitcoin-dev@lists.linuxfoundation.org> wrote:

On 14/05/16 09:00, Andreas Schildbach via bitcoin-dev wrote:
> The whole idea of BIP43 (which BIP44 bases on) is that how these BIPs
> define balance retrieval never changes. This is to make sure you always
> see the same balance on "same BIP" wallets (and same seed of course).

This! Thanks Andreas for formulating my thought that I was not able to
articulate earlier.

Indeed, this would still be the case when using a new BIPXX to define adding segwit chains to what were previously BIP43/44 wallets. In this case retrieval of a BIP44 wallet remains exactly the same as it did before. A BIP44 wallet can still be recovered with any BIP44 compatible wallet software. After you upgrade an existing BIP44 wallet to a BIPXX wallet, now it is no longer a BIP44 wallet. It is now a BIPXX wallet, and can only be recovered using BIPXX compatible wallet software.

If you are concerned about making a new BIP that fits in the BIP43 framework, i.e. a new purpose number, there's no reason this can't also be done. You could create a new purpose number YY. Wallets that follow BIPYY look just like BIPXX, except that they may only contain segwit address chains, no standard P2PKH address chains.

On Sat, May 14, 2016 at 9:14 AM, Jonas Schnelli via bitcoin-dev <bitcoin-dev@lists.linuxfoundation.org> wrote:

AFAIK: Bip39 import (cross-wallet) is not supported by Schildbachs
android wallet [1] and Electrum [2] and Breadwallet [3].

Breadwallet is BIP39, with the BIP43 purpose 0 derivation path, and I believe Schlindbachs is as well. Electrum has their own format. I don't know if it also supports sweeping other mnemonics and wallet layouts.

Aaron Voisine

co-founder and CEO
breadwallet