November BCH Upgrade Discussion Heats Up After Bitcoin SV Full Node Announcement

Blockchain development firm Nchain has announced the company’s plans to launch a new Bitcoin Cash full node client called ‘Bitcoin SV.’ Lead developer Daniel Connolly has published the specifications for re-enabling old opcodes for the November 2018 BCH upgrade. So far the unpublished codebase has seen vocal support from the mining pool Coingeek, but right now some members of the BCH community are concerned that if no other miners switch to Bitcoin SV, the proposed upgrade could cause incompatibilities.

Will Bitcoin SV’s Proposal be Compatible With Bitcoin ABC?
November BCH Upgrade Discussion Heats Up After Bitcoin SV AnnouncementOn Thursday, August 16 the firm Nchain revealed they are releasing a new BCH full node client that’s claimed to be based on Bitcoin ABC v0.17.2, but with a few different upgrade changes added. Bitcoin SV will include restoring more Satoshi opcodes, removing the opcode per script limit, and raising the block size to 128MB. Further, the leading BCH mining pool Coingeek have stated they will be backing the new client. However, since this announcement, some BCH supporters are concerned about the upgrade coming this November. Issues could occur if groups of miners choose Bitcoin SV’s finalized consensus change proposals, which could be entirely different than the finalized Bitcoin ABC 0.18.0 version. Moreover, depending on the upgrade releases stemming from Bitcoin Unlimited, and other implementations, the Bitcoin SV client could be incompatible with any one of them.

So far the Bitcoin ABC team hasn’t responded to the latest Nchain announcement, and the ABC client release for testing hasn’t arrived. According to the ABC roadmap, after they announced the client’s upgrade changes the codebase was supposed to be delivered by August 15. Instead, the team published an article on the benefits of canonical transaction ordering with help from articles written by the Bitcoin Cash miner Jonathan Toomim, and Joannes Vermorel’s study on the process. So at the time of writing the latest 0.18.0 Bitcoin ABC version is two days late. Furthermore, if v0.18.0 contains canonical transaction ordering, the enforcement of minimum transaction size, and the activation of OP_CHECKDATASIG and OP_CHECKDATASIGVERIFY, it will not be compatible with SV’s framework for November.

Bitcoin SV’s Lead Developer Publishes Re-Enabling Old Opcode Specs
The Bitcoin SV client’s lead developer, Daniel Connolly, has published a document of specifications concerning the SV clients’ re-enabling old opcodes. The Bitcoin SV version 1.0 document details that in May of 2018 a few disabled opcodes were re-added to the Bitcoin Cash scripting engine, and this November SV will introduce four more opcodes.

“The scope of that change was limited in order to focus developer attention rather than attempting to reintroduce all of the disabled opcodes at once,” explains the Bitcoin SV spec sheet published on August 17.

This specification expands upon that change by reintroducing additional opcodes — The specifications describe the opcodes that will be added in the November 2018 protocol upgrade.

The re-enabled opcodes will include:

OP_MUL — Multiplies two numbers
OP_RSHIFT — Right shift b by n bits
OP_LSHIFT — Left shift b by n bits
OP_INVERT — Bitwise NOT
The Ultimate Decision Will Be Made With Hashpower
Essentially the ultimate decision making will be in the hands of the miners if they want to upgrade the block space to 128MB, or follow through with ABC’s plans. At the moment there are many different takes on this situation from a wide variety of BCH supporters. Some agree with Coingeek and Nchain and want to raise the space available in blocks, while others believe there isn’t a need for the increase, because current 32MB blocks are not yet being filled. Discussions concerning the matter have increased exponentially on BCH-centric Slack and Telegram channels, Twitter, and Reddit forums.

A lot of BCH supporters believe that ultimately those who have hash power will have the final say in this debate and miners will choose which client they plan to use. Some BCH proponents are not too concerned with the possibility of incompatible clients just yet, because as far as ABC v0.18.0 and SV 1.0 are concerned, neither client has finalized plans for November’s upgrade. As mentioned above the ABC code is not ready yet and the SV 1.0 codebase plans to launch this September.

A lot of BCH supporters believe ultimately it will be the decision of the miners on whether or not they support changes like canonical transaction ordering and OP_CHECKDATASIGVERIFY, or re-enabled opcodes and a 128MB block size increase.
News.Bitcoin.com briefly spoke with Bitcoin XT developer Tom Harding about the recent Nchain announcement and he explained the XT client will follow the majority hashrate.

“XT hasn’t been a driving force behind any of the forking change proposals this time around — We’ve been focusing on non-consensus 0-conf work,” Harding explains.

Regarding consensus changes, our intention is to support what the majority of hashpower wants to do — We’re also thinking about how best to know what BCH miners actually want.

What do you think about the Bitcoin SV client and the possibility of it being incompatible with Bitcoin ABC’s November upgrade? Which upgrade proposals would you like to see finalized? Let us know your opinion on this subject in the comment section below.