[Bitcoin-development] Version bits proposal

[Luke Dashjr]

On Wednesday, May 27, 2015 1:48:05 AM Pieter Wuille wrote:
> Feel free to comment. As the gist does not support notifying participants
> of new comments, I would suggest using the mailing list instead.

I suggest adding a section describing how this interacts with and changes GBT.

Currently, the client tells the server what the highest block version it 
supports is, and the server indicates a block version to use in its template, 
as well as optional instructions for the client to forcefully use this version 
despite its own maximum version number. Making the version a bitfield 
contradicts the increment-only assumption of this design, and since GBT 
clients are not aware of overall network consensus state, reused bits can 
easily become confused. I suggest, therefore, that GBT clients should indicate 
(instead of a maximum supported version number) a list of softforks by 
identifier keyword, and the GBT server respond with a template indicating:
- An object of softfork keywords to bit values, that the server will accept.
- The version number, as presently conveyed, indicating the preferred softfork 
flags.

Does this sound reasonable, and/or am I missing anything else?

Luke