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kona-client is the bare-metal fault proof program that executes the OP Stack state transition on a MIPS prover. It is the primary fault proof program for OP Stack chains. See the fault proof specs.
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May 25, 2026
LatestStable
v1.5.2

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Overview

This is a patch release of kona-client. It bumps FPVM precompile oracle gas for Glamsterdam (EIP-7904), tightens the interop trace-extension boundary to match op-program, and surfaces malformed output-root preimages explicitly. It is required before Glamsterdam activates on L1; otherwise optional.View full release on GitHub →
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May 12, 2026
Stable
v1.5.1

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Overview

[!IMPORTANT] This release assumes MSRV >= 1.94. You may use https://github.com/ethereum-optimism/optimism/releases/tag/kona-client%2Fv1.2.14 for users not supporting this rust version yet.
[!CAUTION] ⚠️ This release is a critical security fix and is a required update for users kona-client.
This is a patch release of kona-client that includes important bug fixes for state trie handling of destroyed accounts.View full release on GitHub →
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May 12, 2026
Stable
v1.2.14

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Overview

⚠️ This release is a critical security fix and is a required update for users of kona-client/v1.2.13.This is a patch release of kona-client that includes important bug fixes for state trie handling of destroyed accounts.View full release on GitHub →