Ethereum Ropsten Testnet encounters chain split as users fail to upgrade to new version

Istanbul, Ethereum’s upcoming hardfork slated to go live in the coming months, has reportedly encountered problems on the Ropsten Testnet. Initially, the Istanbul upgrade was scheduled to go live on Ropsten Testnet on 2 October at block height #6485846, however since the block times increased, the upgrade occurred before the speculated time. This in turn, resulted in a chain split as several miners had not upgraded and continued to mine the old version.

The issue was first highlighted on AllCoreDev Gitter channel by Aman Pruthi, a software enginner, who pointed out that the Ropsten Testnet was stuck on the Istanbul hard fork block. He said,

“Hi All Ropsten is stuck in the istanbul fork block number 6485846 (looks like miners are still on older geth version). I switched to the new version of geth 1.9.5 and even I am stuck on the same block number please advise how to proceed meanwhile geths on older version are proceeding.”

Notably, this issue was not only prevelant with Geth, but also other Ethereum clients. On a GitHub page, Peter Szilagyi stated that the only possible means of solving this issue was to have people update to the new version and have “Istanbul chain beat the old one.” Szilagyi said,

“Ropsten Istabul fork went ‘south’ as we kind of expected. Most people didn’t upgrade, big miners are on the non-upgated chain, causing all kinds of nasty sync issues (hard to find good peers, hard to pick good peers from many bad ones, heaviest chain is bad, etc). Our current netwrok protocol is unable to split the peers into forking and non-forking sets […]”

Szilagyi also highlighed that the team had proposed an Ethereum Improvement Protocol ‘forkid’ to handle exactly this sort of a scenario. This EIP would have made sure that “a node would not only advertise its genesis hash (useless now), rather a combination of the genesis + all the forks afterwards.” He added,

“Such a mechanism would allow two nodes to cross validate each other and disconnect cleanly if on different confirgured forks, without wasting each other’s time”

This aside, Afri Schoedon, Developer Relations at Parity Tech, pointed out that the time given to users to upgrade was too less. He said, “Two weeks is not enough for clients to release and users to upgrade.”