Mina Mesa upgrade halts zkApps activity for eight hours

The Mina Mesa upgrade on September 3 halted transaction processing for about eight hours as the blockchain transitioned to its Mesa release. Exchanges suspended MINA transfers, and deployed zkApps require new verification keys to resume operations. The interruption included five hours of block production without transactions and three hours with no blocks created. The upgrade reached its 10:00 UTC transaction cutoff, with block producers generating empty blocks for 100 slots before halting at 15:00 UTC. The Mesa package was released at 16:30 UTC, with the first Mesa slot completed by 18:00 UTC. Exchanges were instructed to disable MINA deposits and withdrawals until the Mesa network became operational. The upgrade also modifies the network's cadence, reducing slot time from three minutes to 90 seconds and temporarily limiting zkApp transactions to 12 per block. Deployed zkApps must compile Mesa-compatible keys to process new proof-authorized transactions, as pre-upgrade keys are no longer valid. This update is not a permanent failure; once the new key is recorded, zkApps can resume transactions under Mesa. A fallback mechanism allows verification-key permissions to revert to signature authorization until the key is updated. There is no fixed deadline for migration, and proof-authorized activity remains paused until the updates are completed.