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Mina Mesa Mainnet Upgrade: What the Planned September 3 Network Halt Means

Mina’s Mesa hard fork is scheduled for Sept. 3 with transactions stopping at 10:00 UTC, a full network halt at 15:00 UTC and the first Mesa slot targeted for 18:00 UTC.

September 3, 2026Last updated 10:30 UTC2 min read

Mina Protocol is scheduled to execute the Mesa mainnet upgrade on September 3.

This is a planned hard fork, not an exploit. It belongs in CEXVia because the official plan intentionally stops transaction inclusion and later stops the network entirely for a defined upgrade window.

Official timeline

  • 10:00 UTC — stop-transaction slot
  • 15:00 UTC — stop-network slot
  • 15:00–18:00 UTC — upgrade/archive migration
  • 16:30 UTC — Mesa package target
  • 18:00 UTC — first Mesa slot target

10:00–15:00 UTC: state finalization

From the stop-transaction slot, block producers keep nodes running but consensus no longer accepts new blocks containing ordinary transactions.

Mina says this stabilization phase lasts 100 slots and lets the network converge on the final pre-upgrade state.

Transactions submitted after the stop-transaction boundary may not become part of the state used by Mesa.

Mina explicitly tells exchanges to disable MINA deposits and withdrawals during this period.

15:00 UTC: planned full halt

At the stop-network slot, the network is scheduled to neither produce nor accept blocks.

o1Labs then exports the finalized state and prepares the Mesa release. Archive and Rosetta infrastructure also undergo schema and software upgrades.

18:00 UTC: first Mesa slot

The first Mesa block is targeted for 18:00 UTC.

That does not guarantee every exchange reopens funding at exactly the same time. Each venue must update nodes, validate integration and confirm network stability.

What Mesa changes

Mesa introduces:

  • 90-second slots instead of 180 seconds;
  • larger on-chain state capacity;
  • higher event/action limits;
  • higher zkApp account-update limits;
  • automated hard-fork infrastructure.

These changes affect performance, application design and node operations.

User and exchange risk

The main user-facing risks are temporary transfer unavailability and reconciliation near the stop boundary.

Exchange risks include node upgrade failure, delayed funding reopening, archive-schema incompatibility and API/Rosetta integration issues.

A scheduled MINA withdrawal suspension during this window should not be misreported as exchange insolvency or a Mina hack.

Fallback risk

Mina’s documentation says that if a sufficient threshold of nodes is not ready, a new release and new stop slots may be prepared.

The schedule is official but not an unconditional guarantee.

Evidence Status

Confirmed

  • September 3 upgrade schedule.
  • 10:00 stop-transaction.
  • 15:00 stop-network.
  • 16:30 package target.
  • 18:00 first Mesa slot.
  • Exchange funding pause requirement.

Developing

  • Actual timing.
  • Network density.
  • Exchange reopenings.
  • Upgrade defects.

Risk Assessment

Medium.

What to Watch Next

10:00, 15:00, 16:30 and 18:00 milestones; network stability; exchange funding; archive/Rosetta compatibility; revised stop slots.

FAQ

Is Mina being hacked?

No.

When do transactions stop?

10:00 UTC.

When does the network fully halt?

15:00 UTC.

When is restart targeted?

18:00 UTC.

Will exchanges pause MINA funding?

Yes, Mina instructs exchanges to disable deposits and withdrawals during the upgrade downtime.