Ethereum, the world’s second-largest blockchain, has successfully completed its final upgrade ahead of the long-awaited Merge around, though some early technical issues have watchers nervous.

Known as “Bellatrix,” this upgrade brought Ethereum’s consensus layer, the Beacon Chain, into a ready state for the Merge which is slated to occur around September 15 once the final upgrade, known as “Paris,” goes live. 

Through this process, Ethereum’s main net, which uses a proof-of-work consensus mechanism to verify transactions, will merge with the Beacon Chain to become a proof-of-stake mechanism in which users validate blocks in accordance with how much Ether they have staked in the network.

Following some early celebrations over the successful upgrade, a few analysts noticed the “missed block rate,” the frequency at which the network fails to verify a transaction block, had suddenly spiked. 

As Martin Köppelmann of GnosisDAO highlighted on Twitter, historically this figure was around the 0.5% mark, but shortly after the upgrade had risen to 9% within 600 blocks following the upgrade.

“It shows that Bellatrix caused some issues for some validators,” he wrote. “Nothing dramatic but still a number to keep an eye on.” 

This spike could be due to some validators being not fully upgraded to the latest software, as Ethereum data aggregator shows that just over a quarter of nodes are not yet “Merge-ready.”

If miners are not ready when the final Merge occurs, they risk becoming stuck on an incompatible chain and will be unable to send Ether or participate in the post-merge network, an Ethereum Foundation blog post recently warned. 

Not everyone is happy about the plan to upgrade, however. Some Ethereum miners who have invested heavily in Ethereum mining equipment are concerned their income stream will evaporate once the Merge goes through, as their expensive equipment cannot be repurposed.

For this reason, a group of miners is planning on creating a PoW fork of Ethereum in order to keep generating income through their mining rigs.

While it is unlikely to generate the same level of income it has until now, an Ethereum fork is not without precedent. The current Ethereum network is actually a fork from Ethereum Classic in 2016 and was done to address a hack of 3.6 million Ether on the network.

While both have seen significant price increases over the past several weeks ahead of the Merge, they had both fallen considerably throughout Wednesday trading in Asia. 

Ethereum had lost 7.9% to trade at US$1,511 in the past 24 hours at 1 p.m. in Hong Kong, while Ethereum Classic was down 16.2%, changing hands at US$33.94. 

Sharing a name with one of the primary antagonists in the Harry Potter franchise, the name Bellatrix may have raised some eyebrows among fans of the boy wizard. 

The origins of this name, while equally nerdy, are from a separate field. This upgrade was named after the third-brightest star in the constellation Orion the Hunter, which is 20 million years old. 

In a long-standing tradition, upgrades to the Ethereum consensus layer are named after stars, while upgrades to the execution layer, like the upcoming Paris upgrade, are named after cities.