From: Johnson Lau <jl2012@xbt.hk>
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Date: Thu, 26 Jan 2017 20:57:32 +0800
References: <3264264.qpyyi8nbyQ@strawberry>
To: Tom Zander <tomz@freedommail.ch>,
	bitcoin-dev <bitcoin-dev@lists.linuxfoundation.org>
In-Reply-To: <3264264.qpyyi8nbyQ@strawberry>
Message-Id: <A4EF0301-870D-415C-9E80-36DBBA7F3E65@xbt.hk>
Subject: Re: [bitcoin-dev] Changing the transaction version number to be
 varint
Precedence: list


> On 20 Jan 2017, at 22:02, Tom Zander via bitcoin-dev =
<bitcoin-dev@lists.linuxfoundation.org> wrote:
>=20
> The way to do this is that from a certain block-height the current=20
> transaction format labels bytes 2, 3 & 4 to be unused.
> =46rom that same block height the interpretation of the first byte is =
as=20
> varint.
> Last, we add the rule from that block-height that only transactions =
that do=20
> not lie about their version number are valid. Which means version 1.
>=20
> Do people see any problems with this?
> This could be done as a soft fork.

Yes, because:

a) what you are talking is a hardfork, because existing nodes will not =
be able to deserialise the transaction. They will forever interpret the =
first 4 bytes as nVersion.

b) it is not a =E2=80=9Clie=E2=80=9D to use non-version 1 txs. It is =
permitted since v0.1. And version 2 txs is already used due to BIP68.

c) if you are talking about changing the tx serialisation just for =
network transfer, it=E2=80=99s just a p2p protocol upgrade, not softfork =
nor hardfork

-------------------------

There are 3 ways to introduce new tx formats:

1. through a softfork, and make the old clients blind to the new format. =
That=E2=80=99s the segwit approach

2. through a hardfork. Forget the old clients and require new clients to =
understand the new format. That=E2=80=99s the FlexTran approach (in my =
understanding)

3. p2p only, which won=E2=80=99t affect consensus. No one could stop you =
if you try to copy a block by writing in your native language and pass =
to your peer.

In either way, one could introduce whatever new format one wants.=