Ethereum developers have scheduled the mainnet activation of the Fusaka upgrade for December 3, 2025, as discussed in the 167th Ethereum All Core Developers Call. This will be followed by BPO 1 on December 17 and BPO 2 on January 7, 2026. The 'Proposer-Builder Separation' mechanism from the Glamsterdam upgrade will remain unchanged. No unresolved vulnerabilities were detected in the Fusaka-3, Holesky, and Sepolia testnets, ensuring a smooth transition.