Subject: Re: [Bitcoin-development] BIP16/17 replacement

From: Pieter Wuille <[email-masked]>
Date: Wed, 1 Feb 2012 11:02:08 +0100

Op 1 feb. 2012 10:48 schreef "Andy Parkins" <[email-masked]> het
volgende:
>
> On 2012 January 31 Tuesday, Luke-Jr wrote:
>
> > Both BIP 16 and 17 are backward compatible enough that people can
continue
> > to use the old clients with each other. An upgrade is only required to
> > send to (or create/receive on) the new 3...-form addresses. That being
>
> Is that true?  (I'm happy to be called wrong)
>
> It doesn't seem like it to me.  The new transaction types will be
rejected by
> old clients won't they?  They don't pass IsStandard().

IsStandard() is for accepting transactions into the memory pool.
Non-standard transactions are verified just fine when they are in the block
chain.

BIP16/17 both create transactions that, when interpreted as old scripts,
are valid. The only change to the protocol is that previously-valid
transactions become invalid. As long as a supermajority of miners enforce
the new rules, everyone can happily keep using their old bitcoin client.
They won't create the new transaction type, and don't accept them as
payment, but they will accept the new block chain.

If we do a breaking change to the protocol - such as adding a new
transaction type - ALL users must upgrade. Those who don't will see a fork
of the chain from before the first new-style transaction. That is not the
case now.

-- 
Pieter