Fusaka-enabled Parent Upgrade Notice
This upgrade notice explains what you need to do if you operate a chain or a node running on a Fusaka-enabled Parent.
Note
For ArbOS 50 release information, please visit our Arbos release notes
Date of required actions
| Deadline | Network upgrade | Who needs to upgrade |
|---|---|---|
October 14th 2025 | L1 Sepolia | Arbitrum (Orbit) chains and Arbitrum One/Nova operators |
Dec 3rd 2025 | L1 Mainnet | Arbitrum (Orbit) chains and Arbitrum One/Nova operators |
| N/A | Arb One/Nova upgrades to ArbOS 50 | Learn more about the ArbOS 50 release |
Required Node/Client Configurations for Arbitrum (Orbit) chains and ArbOne/Nova operators on Fusaka enabled parent chain
| Layer | Data Availability | Fallback to blobs enabled | Nitro version | Consenus Layer Client |
|---|---|---|---|---|
| L2 | Rollup | N/A | 3.8.0 or 3.7.6 | See table below |
| L2 | AnyTrust / AltDA | Yes | 3.8.0 or 3.7.6 | See table below |
| L2 | AnyTrust / AltDA | No | No action required | No action required |
| L3 | Rollup | No action needed | No action required | No action required |
| L3 | AnyTrust / AltDA | No action needed | No action required | No action required |
Required configuration for nodes/chains posting blobs to a Fusaka-enabled parent chain
Consensus Client / Nitro Flags for operators (Arbitrum chains or Arbitrum One/Nova) chains posting blobs to a Fusaka-enabled parent chain
| Client | Compatible with Nitro | Required Nitro Flag | Required Beacon Node Flag |
|---|---|---|---|
| Prysm | ✅ | None | --subscribe-all-data-subnets |
| Lighthouse | ✅ | None | --supernode |
| Teku | ✅ | --parent-chain.blob-client.dangerous.skip-blob-proof-verification | --p2p-subscribe-all-custody-subnets-enabled |
| Lodestar | ✅ | None | --supernode |
| Erigon Caplin | ❌ |
To read more about PeerDAS changes and why Layer 2 network operators must connect to an Ethereum beacon chain node with historical blob data, see the historical blobs docs.