The return of OP_RETURN – roadmap to “Genesis” upgrade (February 2020)- Important information for app developers.
Steve Shadders, Chief Technology Officer at nChain, published an article earlier this week titled, “The return of OP_RETURN – roadmap to Genesis part 4”. In it, he discusses the history of OP_RETURN and explains what BSV application developers need to do in the lead up to BSV’s “Genesis” protocol upgrade in February 2020.
As Shadders explains, “OP_RETURN is well known as the simplest mechanism for creating an unspendable output and carrying data within a bitcoin transaction. It’s had a checkered history with being the root cause of one of the worst bugs in Bitcoin’s history and arguably also being a political football that led to the beginning of the great altcoin diaspora”.
This critical problem with the way transactions were handled at the time led Satoshi Nakamoto to implement a change, in an effort to avoid bug. As BSV implements the Genesis upgrade in February 2020, this will change. This means that if you are an app developer making use of OP_RETURN, you need to ensure your app will maintain consistent behaviour now and after the Genesis upgrade.
As Shadders states, Instead of starting your script with OP_RETURN, start it with OP_FALSE OP_RETURN. A locking script that contains this will always fail when it hits this sequence of op codes both now and after the Genesis upgrade. Bitcoin SV v0.2.1 released on 12th July 2019 contains a change to recognize this op code pattern as a standard transaction. So, once the majority of nodes are upgraded to this version there should be no functional difference to your app”.
This is a must-read article for any application developer building on BSV; itclearly outlines not just the history of OP_RETURN, but also the very easy steps needed to ensure that developers can continue to build on the original Bitcoin.

CityonChain
Cityonchain is part of a new trend of services that allow users to earn BSV, and contributes to the new BSV Economy where people actually earn and use BSV, rather than just “buy and HODL”cryptocurrency.
CityonChain is a new on-chain information center organized around cities, similar to Craigslist in the U.S. or 58.com in China which publish local classified ads. Cityonchain will enable localized functions such as jobs posting, merchant ads, trading of goods, and even online dating. Users can claim “ownership” of and manage a city; other users are “visitors” to a city. City owners promote platform functions with economic incentives, and earn BSV from their own activity (such as offering advertising in the city) and from activity of visitors to their city (for example, for chatroom activity, the city owner can earn $0.01 worth of BSV per visitor comment). City visitors can earn BSV by publishing high-quality information (for example, if another user “LIKES” your comment about a city restaurant rating, you will get some cents worth of BSV).
In short, the platform will incentivize both city owners and city visitors to earn BSV with high quality content and user engagement in the city. Cityonchain’s goal is to create many happy and BSV-earning “Chaintizens.”
Satoshi Shout-Out: Operation Data Blast
The Quasar upgrade on Bitcoin SV (BSV) raised the default “hard cap” on block size to 2 gigabytes (GB); mining groups then had the choice to manually set their hard caps to a lower figure, but the greater block size capacity still allowed BSV enthusiasts to collectively upload large data files to the blockchain. On July 28, 2019, some enthusiasts conducted as “User Activated Stress Test” named Operation Data Blast, – and uploaded meaningful media onto Bitcoin’s public blockchain. This included video audio, and even book files.
The consequence of uploading approximately 2.5 GB of content and archiving meaningful, valuable data resulted in a record-breaking four instances of 250+ MB blocks (including two blocks of 256MB – a new world record block size on a public blockchain) and generated many other big blocks. This reinforces the fact that on-chain scaling, larger than anyone thought possible on a blockchain is not only possible but also sustainable.


Figure 1 Satoshi Doodles https://satoshidoodles.com/