In Brief:
- ArbOS 61 “Elara” went live on Arbitrum One and Nova on Aug. 20 at 17:00 UTC after a constitutional ArbitrumDAO vote.
- Stylus contracts can now hold 96 KB of compressed code, up from 24 KB, and dedicated chains get optional protocol-level compliance filtering, customizable priority fees and an alternative data availability interface.
- The chain-owner controls land on the tier that hosts most Arbitrum gaming networks, including Xai, Sanko and Proof of Play Apex.
Arbitrum activated ArbOS 61, codenamed Elara, on Arbitrum One and Nova on Aug. 20 at 17:00 UTC, raising the Stylus contract size limit fourfold and handing operators of dedicated chains a set of controls they didn’t have before.
The upgrade passed as a constitutional AIP and had been running on Arbitrum Sepolia before mainnet activation.
ArbOS Elara is live on the Arbitrum Platform
New for dedicated blockchains:
Protocol-level compliance filtering
Customizable priority fee support
Alternative data API
New on Arbitrum One:
Smarter base fee tuning
4x capacity increase to Stylus contracts@ArbitrumView on X ↗
Compliance filtering arrives at the protocol level
Elara adds optional transaction screening built into the node software. It’s disabled by default on Arbitrum One and Nova, and it’s aimed at operators of dedicated chains that face regulatory obligations in their jurisdictions. Chain owners could configure it as soon as the upgrade went live.
Filtering runs in two places. A Compliance Rules Engine sits inside the sequencer and simulates each transaction before sequencing, rejecting violations so they never enter a block. A second check lives in the state transition function and catches transactions submitted through the parent chain’s Delayed Inbox, failing them during execution and closing the force-inclusion route around the sequencer.
Chain owners configure an external provider to define which addresses are restricted. The Arbitrum documentation names TRM Labs and Chainalysis as examples. The resulting list is held in memory on screening nodes and encoded as salted hashes of the form sha256(salt || address), then refreshed periodically.
Stylus gets four times the room
The Stylus change is the one game developers will hit first. Compressed contract code can now reach 96 KB, up from 24 KB, removing the ceiling that pushed teams to split logic across multiple deployments.
The upgrade also raises the WASM size ceiling and changes WASM multi-value support, which the proposal flagged as capable of affecting existing contracts. The Stylus Rust SDK was updated alongside it.
Stylus is the Rust, C and C++ execution path that runs next to the EVM, and larger contracts matter for the compute-heavy game logic studios have been trying to push on chain.
Fees and data availability
Elara ships multidimensional gas pricing and a new BaseFeeManager contract. The DAO vote lets Offchain Labs move the minimum L2 base fee on Arbitrum One and Nova between 0.01 gwei and 0.10 gwei inclusive, within that band, for two years.
Priority fees are now configurable for dedicated chain operators. Enabling priority fee collection on Arbitrum One itself is separate and requires further ArbitrumDAO votes.
The release adds an optional alternative data availability interface for dedicated chains, and fixes gas refund logic errors carried over from ArbOS 51, codenamed Dia, which Elara builds on.
Where this lands for games
Dedicated chains are where most Arbitrum gaming activity sits. Xai, Sanko and Proof of Play Apex, the chain built by the studio behind Pirate Nation, all run on the Orbit framework with their own gas tokens and fee parameters. Priority fee configuration and base fee tuning are the levers those operators use to keep transaction costs predictable during activity spikes.
The Arbitrum Foundation’s Gaming Catalyst Program, funded with 200 million ARB, deployed a first wave of $10 million to studios including Wildcard, Xai and Pirate Nation.
The documentation is blunt about who compliance filtering isn’t for. It says the feature isn’t intended for use by Arbitrum One, and that folding it into Elara canonicalizes it in the node software and simplifies the codebase. It frames the addition as the platform meeting the needs of teams with obligations to comply with regulatory frameworks in their respective jurisdictions.
Node operators had to be on Nitro v3.11.3 or higher before Thursday’s activation. Anything older fell out of consensus.
