ArbOS Elara: Compliance Filtering, Priority Fee Support
Following approval through Arbitrum governance, the ArbOS Elara upgrade is now live on the Arbitrum Platform, bringing new capabilities to dedicated blockchains and important improvements to Arbitrum One.
New for dedicated blockchains:
- Protocol-level compliance filtering
- Customizable priority fees
- Alternative data API
New on Arbitrum One:
- More efficient base fee tuning process
- 4x increase to Stylus smart contract capacity
Watch the overview video
Protocol-level compliance filtering for dedicated blockchains
If the next generation of financial markets are going to interact with the programmable economy, they will need infrastructure that can adapt to their rules, users, and operating environments. We provide new protocol-level compliance filtering as policies that can be defined by the chain owner. Policies can be applied at the sequencer and state transition function layer to filter transactions before execution. The chain owner also receives records of filtered transactions via API report for internal reviews and audits.
Ultimately, this gives businesses a clearer path to launching regulated onchain products without sacrificing the flexibility and control that dedicated chains provide.
Priority fee support for dedicated blockchains
ArbOS Elara adds support for priority fee collection on dedicated blockchains, giving chain operators another configurable tool for transaction ordering and fee-market design. Priority fees allow transactions to include tips that influence transaction ordering, creating greater flexibility for chains with advanced execution, trading, or application-specific requirements.
Importantly, this upgrade establishes the underlying capability required for future priority fee collection on Arbitrum One, an important step toward implementing Priority Gas Auction (PGA) transaction ordering for the network. This potential upgrade is being discussed separately through ArbitrumDAO governance.
Alternative Data API for dedicated blockchains
The new Alternative Data Availability (AltDA) API enables chain operators to integrate data availability providers without maintaining custom Nitro forks. This significantly reduces long-term maintenance requirements and allows teams to focus on product development rather than infrastructure upkeep.
Note that Arbitrum One is not expected to use this API because its transactions settle on Ethereum L1.
Improved base fee tuning for Arbitrum One
Arbitrum One now uses a BaseFeeManager contract that allows the network to respond more effectively to changing market conditions that affect user costs, spam resistance, network activity, and fee revenue.
The contract grants Offchain limited authority to adjust the minimum L2 base fee within ArbitrumDAO-approved boundaries of 0.01 – 0.10 gwei. This authority is bounded, transparent, and expires two years after mainnet activation. Any adjustment will follow public notification through the Arbitrum forum, and the ArbitrumDAO would retain the ability to remove the delegation through the standard governance process at any time.
This change does not automatically increase fees. Instead, it establishes a governance-approved mechanism for limited, but quick, adjustments should future network conditions warrant them.
Increased Stylus smart contract capacity
To help teams building larger Rust-based applications with Stylus, the contract code size limit has increased from 24KB to 96KB. This greatly reduces the need to split applications across multiple contracts and simplifies development workflows, particularly for teams using larger Rust libraries.
Additionally, this upgrade includes bug fixes and compatibility changes, including the removal of support for the WebAssembly multi-value extension. Contracts relying on multi-value WASM will no longer be able to be activated or reactivated, so Stylus developers should review the relevant compatibility notes before upgrading.
This change applies only to Stylus contracts. It does not change the Solidity contract size limit or alter EVM contract-size rules.
Build your solution with the Arbitrum Platform
ArbOS Elara advances a core principle of the programmable economy: blockchain infrastructure should adapt to the needs of the organizations building on it while preserving the performance, security, and interoperability of the broader Arbitrum ecosystem.
Learn more about the Arbitrum Platform’s new protocol-level compliance filtering, or contact the Offchain team to help design, launch, and scale your custom solution.
*Any mentions of future products intended for the Arbitrum One network will be subject to a vote by the Arbitrum DAO.