Mina Mesa upgrade completes, but zkApps remain offline until key migration
Chain moves forward while app functionality stays paused
The Mina blockchain finished its Mesa upgrade after an eight-hour network pause on September 3. The hard fork moved the layer-1 blockchain to its new Mesa release. However, zero-knowledge apps (zkApps) running on the network cannot yet resume proof-authorized activity. They need to migrate to new verification keys compatible with the upgrade.
Exchanges stopped MINA transfers during the upgrade process. While the network is now active, each exchange controls when it will restart transfer support for the token.
Key numbers from the upgrade timeline
- The network halted transactions at 10:00 UTC on September 3.
- Mina reached its transaction cutoff and produced empty blocks for 100 slots before a complete halt at 15:00 UTC.
- The Mesa package was released at 16:30 UTC.
- The first Mesa slot completed at 18:00 UTC.
- Slot time is now reduced from three minutes to 90 seconds.
- zkApp transactions are temporarily capped at 12 per block.
Official upgrade status
Mina’s official upgrade runbook marks the transaction cutoff, the package release, and the first Mesa slot as completed milestones. Archive-node and manual node upgrades were still in progress as of the morning of September 4.
Protocol changes and compatibility requirements
The Mesa upgrade changes protocol constants and circuit constraints. This means proofs generated with old verification keys no longer verify on the new network.
Deployed zkApps cannot process new proof-authorized transactions until developers compile a Mesa-compatible key using o1js 3.0 and update the key stored on-chain. This is an on-chain compatibility update rather than a permanent failure of the deployed contract.
Migration path for affected apps
Mina has put in place a temporary fallback mechanism during this transition.
Verification-key permissions set to "proof" or "impossible" will fall back to signature authorization. An access permission set to "proof" receives the same fallback, but a permission set to "impossible" remains locked. Once a zkApp updates its key successfully, the account’s transaction version advances and the original verification-key permission rules return.
What remains uncertain
There is no fixed migration deadline set by Mina. The fallback authorization remains active indefinitely until a specific zkApp updates its key. Until then, proof-authorized activity for that app remains paused even though the underlying chain is operational.
Why this matters for the ecosystem
The upgrade demonstrates the maintenance required when a blockchain changes its underlying cryptographic constraints. While normal network operation has resumed, the downtime for specific zero-knowledge applications continues until individual developers complete their key migrations.
