OP Labs announced the upgrade of the OP Sepolia test network on March 19th, which includes the inclusion of unauthorized OP Stack fault proofs. Developers using bridges, centralized exchanges, and custom withdrawal solutions on OP Stack will need to make logic changes due to the introduction of destructive changes. Due to fault-tolerant integration, withdrawals between OP Sepolia and Sepolia now require a processing time of seven days. The OP Stack fault-tolerant system consists of three main elements: the Fault-proof Program (FPP), the Fault-proof Virtual Machine (FPVM), and the Dispute Resolution Game Protocol.