Deep Dive
1. ArbOS Dia Upgrade (29 December 2025)
Overview: Introduces predictable gas pricing and enhanced developer tools, aligning with Ethereum’s Fusaka upgrade for improved interoperability.
The upgrade leverages Ethereum’s Fusaka codebase to streamline transaction finality and reduce gas volatility. It also adds mobile-friendly authentication protocols for enterprise applications.
What this means: This is bullish for Arbitrum because users gain more stable transaction costs, while developers can build cross-chain apps more efficiently. (Source)
2. Fusaka Scalability Boost (18 December 2025)
Overview: A backend upgrade targeting 30% higher throughput by optimizing batch processing and state commitments.
Fusaka refines Arbitrum Nitro’s fraud-proof mechanism, reducing latency during congestion. Node operators must update clients by 5 January 2026 to avoid sync issues.
What this means: This is neutral for Arbitrum as it maintains technical parity with Ethereum but requires timely node upgrades. Scalability improvements could attract high-frequency dApps. (Source)
3. $14M Audit Program Launch (28 July 2025)
Overview: ArbitrumDAO approved 30M ARB tokens to fund security audits for early-stage projects, reducing exploit risks.
Projects must use pre-vetted auditing firms, with grants covering up to 80% of audit costs. A committee oversees fund allocation to ensure alignment with network security priorities.
What this means: This is bullish for Arbitrum because it lowers barriers for developers while strengthening ecosystem trust. (Source)
4. ArbOS 40 “Callisto” (24 May 2025)
Overview: Enabled native account abstraction via EIP-7702, letting wallets act as smart contracts temporarily.
The upgrade added BLS signature aggregation (EIP-2537) for cheaper ZK-proof verification and historical block hash access (EIP-2935) for oracle reliability.
What this means: This is bullish for Arbitrum because users can pay fees in any token, and developers gain tools for advanced dApps. (Source)
Conclusion
Arbitrum’s 2025 upgrades focused on scalability, user experience, and Ethereum synergy—key drivers for maintaining its Layer 2 dominance. With Fusaka and Dia enhancing throughput, and audits bolstering security, can Arbitrum sustain its 40%+ market share among Ethereum rollups in 2026?