Optimism announced it will discontinue support for op-geth and op-program on May 31, 2026, marking a major technical shift for Ethereum layer-2 chains built on its stack. All new features, including the upcoming Karst hard fork, will be developed exclusively for op-reth, meaning networks must migrate before Karst to stay aligned with the mainnet. The op-program’s fault proof mechanism will transition to kona-client, Optimism’s new fault proof system designed for increased security and performance.