# Kona v1.8.0 corrects conditional fault-proof derivation and execution behavior

> Available proof software now checks singular-batch parent hashes against the safe head after Holocene and stops on errors that do not prove payload invalidity. Host fixes also address TLS and preimage handling.

- URL: https://riadefi.com/on-chain/2026-10-01-optimism-kona-v1-8-0-proof-corrections/
- Type: Upgrade or migration
- Stage: Confirmed
- Evidence: confirmed
- Materiality: material
- Event date: 2026-10-01
- Version: 1, published 2026-10-05 (first published 2026-10-05)
- Follow-up: 2026-10-08
- Advisor-relevant: no
- Affects: Optimism canonical bridge (protocol)

## What happened

OP Labs released recommended Kona host and client updates correcting proof-program derivation and error handling, with new absolute prestates required.

## What changed

Available proof software now checks singular-batch parent hashes against the safe head after Holocene and stops on errors that do not prove payload invalidity. Host fixes also address TLS and preimage handling.

## What did not change

Release publication does not establish deployment of the new prestates or changed live withdrawal rules. The notice does not report stolen funds or an exploited bridge.

## Confirmed

- The official records recommend host and client v1.8.0.
- The prior parent-hash check could allow a malformed batch from a faulty batcher to produce derivation different from op-node.
- The release states fault proofs are unaffected unless the batcher misbehaves.
- Non-invalidity execution errors now stop the proof program rather than producing a deposit-only block.
- The client requires new absolute prestates and the host must use them.

## Still open

- Whether OP Mainnet's live dispute games use an affected Kona prestate.
- Whether the corrected prestates have been adopted by governance and active proof infrastructure.
- Whether any malformed-batch divergence occurred in production.

## What it means for an advisor

- Review the Optimism bridge diligence file's proof implementation and live prestate mapping.
- Verify adopted prestates and operator compatibility before recording this release as completed remediation.

## Sources

1. [kona-host v1.8.0](https://github.com/ethereum-optimism/optimism/releases/tag/kona-host/v1.8.0) · OP Labs / ethereum-optimism · 2026-10-01
2. [kona-client v1.8.0](https://github.com/ethereum-optimism/optimism/releases/tag/kona-client/v1.8.0) · OP Labs / ethereum-optimism · 2026-10-01


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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.