Catenaa, Wednesday, August 26, 2026- Arbitrum has activated its ArbOS 61 “Elara” upgrade, adding optional compliance filtering for custom Orbit chains and expanding the size allowed for Stylus smart contracts.
The upgrade went live Aug. 20, according to information from Arbitrum and Offchain Labs cited by Bitcoinist.
Node operators must update to Nitro version 3.11.3 to support the release.
Elara’s most closely watched feature is a protocol-level filtering option intended for operators of customized Arbitrum Orbit chains.
The feature does not impose transaction filtering on the public Arbitrum One or Arbitrum Nova networks.
Instead, individual Orbit operators can choose whether to deploy the compliance controls according to their own business or regulatory requirements.
The distinction is important because protocol-level filtering can raise concerns about censorship in decentralized networks.
Arbitrum’s implementation is aimed primarily at private, regulated or enterprise deployments rather than changing the rules governing its public Layer 2 networks.
Orbit allows developers and companies to create customized blockchains using Arbitrum technology.
Operators can configure features including governance, transaction processing, fee structures and other network parameters.
Elara adds compliance filtering to those choices.
A financial institution developing a private Orbit chain, for example, could use transaction controls if required to meet sanctions, anti-money laundering or other regulatory obligations.
A chain designed for open public use could leave the feature disabled.
The approach allows Arbitrum to serve regulated applications without imposing the same controls across its broader ecosystem.
The upgrade reflects Arbitrum’s expansion beyond operating a single Ethereum scaling network.
Its ecosystem now includes Arbitrum One, Arbitrum Nova and Orbit, which allows projects to deploy their own customized chains.
That model increasingly puts Arbitrum in competition with other blockchain infrastructure providers seeking to supply technology for application-specific and institutional networks.
Enterprise users often require capabilities that public blockchains do not normally prioritize.
Those can include transaction permissions, compliance screening, customized gas systems and tighter operational control.
Such requirements have created tension within the blockchain sector.
Public blockchain supporters often prioritize permissionless access, while regulated financial institutions may be legally unable to operate without transaction restrictions.
Arbitrum’s solution is to separate those models.
Public networks can remain open while operators building specialized Orbit chains gain additional configuration options.
Elara also introduces a major change for developers using Arbitrum Stylus.
The maximum Stylus smart contract size increases from 24 kilobytes to 96 KB.
That fourfold increase gives developers greater room to deploy larger and more complex applications.
Stylus allows developers to build Arbitrum smart contracts using programming languages including Rust, C and C++, alongside the Solidity-based environment commonly associated with Ethereum.
The technology is intended to expand the developer pool beyond programmers already familiar with Ethereum-specific languages.
Larger contract limits could make Stylus more practical for applications containing heavier codebases or more complicated computational logic.
It could also make migration easier for developers bringing existing software into blockchain environments.
Orbit has become an important part of Arbitrum’s wider strategy.
Instead of requiring every application to operate on the same public Layer 2, developers can create chains tailored to individual products.
That approach is increasingly common across Ethereum scaling.
Gaming projects may want different transaction costs and performance characteristics from financial applications.
Institutional tokenization platforms may require compliance functions that a fully permissionless network does not offer.
High-volume applications may want control over gas tokens and network economics.
Orbit is designed to allow those differences while keeping the chains connected to Arbitrum and Ethereum infrastructure.
Elara extends that flexibility into regulatory controls.
The filtering feature is likely to attract debate because it introduces the ability to restrict activity directly at the protocol level.
For regulated institutions, that capability may be necessary.
Banks, asset managers and companies handling tokenized securities can face legal obligations to prevent transactions involving sanctioned entities or unauthorized users.
For supporters of censorship-resistant blockchains, protocol-level filtering can conflict with the principle that networks should process valid transactions without discrimination.
Arbitrum’s design attempts to address both positions by making the feature optional.
An Orbit operator can adopt compliance controls without requiring Arbitrum One users to accept them.
That places the decision with the organization operating the customized chain.
Users of Arbitrum One and Nova should not interpret Elara as the introduction of a new censorship system across Arbitrum.
The filtering mechanism is configuration-dependent and aimed at Orbit deployments.
That makes Elara different from a network-wide rule imposed on every Arbitrum transaction.
The upgrade instead expands the range of networks that can be built using Arbitrum technology.
Some can remain completely open.
Others can be designed for environments where access or transactions must meet regulatory conditions.
This distinction could become increasingly important as financial institutions experiment with tokenized assets and blockchain settlement.
Elara arrives as Offchain Labs is also working on deeper changes to Arbitrum’s settlement architecture.
The company is separately developing a plan to integrate zero-knowledge proofs into the BoLD system to potentially reduce withdrawals from about seven days to hours.
Unlike Elara, that proposal has not been deployed and still requires governance approval.
Taken together, the developments show Arbitrum pursuing two different objectives.
One is improving the technical performance of its public Layer 2 infrastructure.
The other is making its technology more adaptable for developers and institutions building customized chains.
Elara belongs primarily to the second category.
The value of the compliance feature will ultimately depend on whether enterprises use it.
If financial institutions and tokenization projects begin launching Orbit chains with Elara’s controls enabled, Arbitrum could strengthen its position in enterprise blockchain infrastructure.
If demand for protocol-level filtering remains limited, the larger Stylus contract size may prove to be the upgrade’s more important long-term contribution.
Either way, Elara illustrates how Ethereum scaling networks are evolving.
Competition is no longer limited to transaction speed and fees.
Blockchain platforms are increasingly competing over developer tools, customization, institutional compatibility and the ability to support different regulatory models.
Arbitrum’s answer is to let customized chains make those choices themselves.
