Arbitrum’s ArbOS 61 ‘Elara’ upgrade is live, but its headline features are not switched on for Arbitrum One or Nova. Official documentation says it raises Stylus capacity from 24 KB to 96 KB and adds a BaseFeeManager for minimum L2 base fees. Optional compliance filtering and AltDA tooling target custom chains, not public networks by default. Independent coverage confirms priority-fee collection on Arbitrum One still needs a separate DAO vote. For builders, this means more capacity and configurable infrastructure, not an instant fee or performance revolution. Node operators should verify Nitro compatibility. The impact depends on which features each chain activates.