That's a valid concern, but I don't see the conflict here. In order to recover funds from a wallet conforming to BIPXX, you must have wallet software that handles BIPXX. Simply making BIPXX backwards compatible with previously created BIP44 or BIP43 purpose 0 wallets doesn't change this at all.

Aaron Voisine

co-founder and CEO
breadwallet

On Fri, May 13, 2016 at 10:57 AM, Pavol Rusnak <stick@satoshilabs.com> wrote:

On 13/05/16 18:59, Aaron Voisine wrote:
> This scheme is independent of the number of accounts. It works with BIP44
> as well as BIP43 purpose 0, or any other BIP43 purpose/layout. Instead of
> overloading the account index to indicate the type of address, you use the
> chain index, which is already being used to indicate what the specific
> address chain is to be used for, i.e. receive vs change addresses.

I see the advantage here. But there is a major problem here.

We came up with BIP44 so a wallet can claim it is BIP44 compatible and
you can be 100% sure that you can migrate accounts from one wallet
implementation to another. This was not previously possible when a
wallet claimed it is BIP32 compatible.

Now we have a similar problem. When there is a BIP44 wallet, does it
mean it supports segwit or not? For this reason I would like to see
another BIPXX for segwit, so a wallet can claim it is BIP44, BIP44+BIPXX
or BIPXX compatible and you'll know what other wallets are compatible
with it.

--
Best Regards / S pozdravom,

Pavol "stick" Rusnak
SatoshiLabs.com