A few weeks ago I published an article giving an overview of an idea that has been circulating in the Bitcoin community for several years. I believe it was Adam Back that coined the term “extension blocks” and a few years prior to that, Johnson Lau proposed the idea as “auxiliary blocks.” I deliberately avoided the use of either term on advice from a Bitcoin Core developer (who thought the term was too politically charged). So I tapped into my well of creativity and called them “secondary blocks.”

I wrote the article out of concern the community was (and may still be) headed toward a contentious hard fork, something we believe is best avoided. We want to be supportive of alternative Bitcoin implementations and the teams behind them, but we feel Bitcoin Unlimited has made a few poor technical decisions. At the same time, I am concerned that many people may not be aware of extension blocks and how they may be a better way to upgrade Bitcoin and avoid unnecessary contentious hard forks.

Shortly after publishing that article, the bcoin team reached out to inform me that they had nearly completed an implementation of extension blocks. I was very excited and knowing JJ (who used to work at BitPay), I had a feeling it was going to be very good. For the next few weeks, JJ and the team worked tirelessly to get a complete working implementation that could be demonstrated. They felt working code made a far more compelling case for the technology than just another article on the topic. I agree!

The bcoin team has released specifications and working code for the developer community to critique. At BitPay, we think this idea of extension blocks holds a lot of promise, and we intend to participate in its technical evaluation. A public tesnet running extension blocks is available now with easy to follow instructions. You can be running a bcoin node on this extension block testnet in just few minutes. If it holds up to scrutiny, we may support activation on the main net.

If you would like to see Bitcoin advance, extension blocks deserves your consideration. Your participation in the testnet would be of great service to the community.

Interested in solving these challenges? BitPay is hiring.