[Standard] Ethereum Mainnet and Testnets - Upgrade to Nethermind v1.39.3

Scheduled for Sep 17, 01:00 - 05:00 UTC

Scheduled

We are upgrading our Ethereum Mainnet and Testnet nethermind infrastructure to v1.39.3. This release consolidates several updates published since v1.38.0, most notably a security update to underlying .NET dependencies addressing multiple CVEs, along with reliability and hardening fixes to request decoding and memory handling.

During the maintenance window, brief interruptions to RPC availability may occur.

RPC changes:
- The non-spec error field has been removed from transaction receipt responses.
- eth_simulateV1 now bounds total block expansion across a simulation request.

https://github.com/NethermindEth/nethermind/releases/tag/1.39.3

Posted Sep 09, 2026 - 16:40 UTC

This scheduled maintenance affects: Ethereum (Mainnet — JSON-RPC API, Sepolia — JSON-RPC API, Hoodi - JSON-RPC API).