The Metal DAO community has approved activation of Upgrade 19 / Karst on Metal L2.

Upgrade 19 aligns Metal L2 with the latest OP Stack release and helps ensure the network remains stable, secure, and fully maintained during the transition period leading up to the Homecoming migration.

While Metal L2’s long-term direction is the move toward a sovereign Metal Blockchain subnet, as authorized by MIP-002: Homecoming, maintaining the current OP Stack deployment remains important for operational continuity, partner integrations, and user experience.

For more on Homecoming, visit:
https://metalhomecoming.com

What Is Upgrade 19?

Upgrade 19, also known as the Karst hard fork, is the latest OP Stack network upgrade from OP Labs.

For Metal L2, this upgrade introduces several important protocol improvements, including:

• L2 Contract Manager (L2CM) — a new mechanism for governance-approved L2 smart contract upgrades

• OPCMv2 — the redesigned OP Contracts Manager used for Upgrade 19

• CANNON_KONA — promoted to the respected fault proof game type

• Osaka EIPs on L2 — including the EIP-7825 per-transaction gas limit

• Glamsterdam Defense — a preemptive security change reducing the maximum BN256 pairing precompile input size

The full OP Labs technical notice is available here:
https://docs.optimism.io/notices/upgrade-19

Activation Timeline for Metal L2

OP Labs has published the planned activation schedule for Upgrade 19 / Karst.

For Mainnet OP Stack chains, including Metal, Upgrade 19 is planned to activate on:

Wednesday, July 8, 2026 at 16:00:01 UTC

The OP Labs notice also lists the Unix timestamp:

1783526401

This value is a Unix timestamp, not a block height.

The smart contract upgrades are expected to occur during the week prior to activation. Activation remains dependent on Optimism Governance approval and the official OP Stack upgrade process.

Metal L2 is listed by OP Labs among the chains included in this upgrade, alongside OP, Soneium, Ink, Unichain, Mode, and Zora.

Why This Matters for Metal L2

Even though Metal L2 is preparing for the Homecoming migration to Metal Blockchain, the current OP Stack deployment remains active and must continue to be maintained responsibly.

Approving Upgrade 19 helps ensure Metal L2 remains aligned with the latest OP Stack protocol changes during this transition period.

This supports:

Operational continuity — helping prevent compatibility issues during migration

Exchange and partner integrations — supporting uninterrupted infrastructure and ecosystem support

User experience — maintaining a stable network for current Metal L2 users

Network security — staying current with OP Stack fault proof and protocol improvements

Important Operator Requirements

Node operators and infrastructure providers supporting Metal L2 must upgrade required off-chain components before the activation timestamp.

OP Labs has stated that op-geth and op-program will not support Upgrade 19 / Karst.

Operators must migrate to:

• op-reth

• kona-client for fault proofs

before activation.

End of support for legacy components is scheduled for:

May 31, 2026

Operators running permissionless fault proof infrastructure must also ensure op-challenger is configured to support cannon-kona ahead of the upgrade.

What This Means for Application Developers

Most applications running on Metal L2 are expected to be unaffected by Upgrade 19.

However, developers should review the OP Labs notice and verify compatibility if their application:

• submits L2 transactions with very high gas limits

• interacts with MODEXP or P256VERIFY precompiles

• uses BN256 pairing precompile calls with large inputs

• interacts directly with OP Stack predeploy contracts

• manages custom withdrawal proving infrastructure

After Upgrade 19, L2 transactions will be subject to the EIP-7825 per-transaction gas limit. Deposit transactions are exempt.

For most applications, no immediate action is expected.

Governance Result

The Upgrade 19 proposal has passed Metal DAO governance.

Thank you to the $MTL community for reviewing and voting.

With governance approval secured, the Metal L2 engineering team can proceed with the required coordination and operator preparations ahead of the official OP Stack activation timeline.

Proposal:
https://gov.xprnetwork.org/communities/4/proposals/69fb83f48bf261930c09aeef

Looking Ahead

Upgrade 19 is part of our ongoing commitment to maintain Metal L2 securely and responsibly throughout the Homecoming migration.

Metal L2’s long-term direction remains the move toward a sovereign Metal Blockchain subnet architecture. During this transition, we will continue to support the current OP Stack deployment and coordinate required upgrades to maintain continuity for users, developers, partners, and infrastructure providers.

For more on the broader migration plan, visit:
https://metalhomecoming.com

— The Metallicus Team