# Kona discloses fault-proof soundness fixes and requires operator upgrade

> The available release fixes proof soundness and execution behavior. Operators using kona-client fault proofs are instructed to upgrade, and the changed state transition requires a new absolute prestate.

- URL: https://riadefi.com/on-chain/2026-09-08-optimism-kona-1-7-0-fault-proof-soundness/
- Type: Upgrade or migration
- Stage: Confirmed
- Evidence: mixed
- Materiality: material
- Event date: 2026-09-08
- Version: 1, published 2026-09-15 (first published 2026-09-15)
- Follow-up: 2026-09-10
- Advisor-relevant: no
- Affects: Optimism canonical bridge (protocol)

Developing. Some claims here are not yet confirmed; they are listed apart from the confirmed facts. A new version replaces this one when the primary evidence changes.

## What happened

Optimism published Kona client and host v1.7.0, documenting derivation discrepancies that could let a Byzantine batcher cause Kona and op-node to derive different chains from identical L1 data.

## What changed

The available release fixes proof soundness and execution behavior. Operators using kona-client fault proofs are instructed to upgrade, and the changed state transition requires a new absolute prestate.

## What did not change

Publication does not establish production installation or on-chain prestate activation. Lagoon interoperability remains outside production according to the release notes.

## Confirmed

- Both official releases identify the upgrade as required for chains running kona-client fault proofs.
- The client notes disclose span-batch decoding and decompression discrepancies relative to op-node.
- The proof execution change requires a new absolute prestate.
- The host release also fixes a beacon-blob deserialization crash.

## Still open

- Whether the watched Optimism bridge's active production dispute games depend on affected Kona versions.
- Which production operators have installed the release and which absolute prestates are authorized on-chain.
- Whether any disclosed defect was exploited; the release records do not establish exploitation or losses.

## What it means for an advisor

- Review the Optimism bridge diligence file's fault-proof implementation and active dispute-game assumptions.
- Obtain production implementation, operator-version, and authorized-prestate evidence before treating this release as completed remediation.

## Sources

1. [kona-client/v1.7.0](https://github.com/ethereum-optimism/optimism/releases/tag/kona-client/v1.7.0) · Optimism · 2026-09-08
2. [kona-host/v1.7.0](https://github.com/ethereum-optimism/optimism/releases/tag/kona-host/v1.7.0) · Optimism · 2026-09-08


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Published by Ketju Research on RIADeFi (https://riadefi.com). Educational research for financial professionals; not investment, legal, tax, or compliance advice.