Arbitrum activated ArbOS 61 Elara on Aug. 20, adding optional protocol-level transaction screening, priority-fee support and an alternative data-availability interface for dedicated chains, while changing base-fee administration and expanding Stylus capacity on Arbitrum One.
The upgrade went live after approval through Arbitrum governance. The governance proposal included compliance and priority-fee capabilities in ArbOS 61 but left them intentionally disabled on Arbitrum One and Nova. The compliance filter is therefore not a new screening system for users of Arbitrum One; it is configurable tooling for owners of dedicated Arbitrum chains.
Arbitrum's technical documentation says compliance filtering is off by default and that chain owners must explicitly configure and enable each component. An owner can select an external compliance provider, such as TRM Labs or Chainalysis, to produce a restricted-address list and can define rules covering transfers, contract calls and other interactions involving those addresses.
Enforcement operates at two levels. The sequencer simulates transactions and rejects those that violate the configured rules before they enter a block. For transactions submitted through the parent chain's Delayed Inbox, a sentinel can register the transaction hash with an onchain guardian so the state transition function forcibly fails it when it is included.
