Ethereum developers are regrouping this week after researchers discovered a security flaw in the code of a planned upgrade. The long-awaited fork, known as “Constantinople,” will now take place in late February. While the discovery of the vulnerability raised alarms, it highlights the role of a new type of business that cropped up with the rise of blockchain: companies that specialize in auditing these networks for security flaws. In this case, it was ChainSecurity that spotted the problem.

Also in the news this week: John McAfee says in a tweet that he is being charged with using cryptocurrencies in “criminal acts against the U.S. government.” And Overstock’s security token trading platform, tZero, is set to launch, according to the company. Can an early internet giant reinvent itself for the blockchain world? We examine some of the factors that could affect Overstock’s bet that token-based securities will be the next big thing in finance.