Ahh. I see. Thanks, I must have missed that when going through the BIP.
Guess I need to read more carefully next time.

Thanks,
Andrew

On Fri, Jan 22, 2016 at 11:11 PM David A. Harding <dave@dtrt.org> wrote:

> On Fri, Jan 22, 2016 at 04:36:58PM +0000, Andrew C via bitcoin-dev wrote:
> > Spending a time locked output requires setting nSequence to less than
> > MAX_INT but opting into RBF also requires setting nSequence to less than
> > MAX_INT.
>
> Hi Andrew,
>
> Opt-in RBF requires setting nSequence to less than MAX-1 (not merely
> less than MAX), so an nSequence of exactly MAX-1 (which appears in
> hex-encoded serialized transactions as feffffff) enables locktime
> enforcement but doesn't opt in to RBF.
>
> For more information, please see BIP125:
>
>     https://github.com/bitcoin/bips/blob/master/bip-0125.mediawiki
>
> -Dave
>
>