So many users are dependent on Ethereum client Geth that a bug could temporarily freeze the network – something blockchains aren't supposed to do, ever. In light of this, Ethereum Core developers decided to postpone work on the Berlin hard fork until at least August in an effort to give other clients a chance to increase their share of the network.
Geth makes up only one of 11 client specifications, but 79% of Ethereum nodes run on it, according to Ether Nodes. That percentage is also up 5% since December. Developers worry that a serious bug could break Ethereum – particularly as rolling updates to Eth 1.x continue before the network transitions to a Proof-of-Stake (PoS) consensus algorithm under Eth 2.0.
"Geth is the majority of the network," Geth team leader Péter Szilágyi said in last Friday's All Core Developers group call. "It's super important that we are correct because we cannot afford to not be correct."