Mina declared Berkeley upgrade complete, putting zkApps on mainnet

Mina Protocol publicly declared its Berkeley mainnet upgrade complete on June 7, 2024, bringing programmable zero-knowledge applications—called zkApps—to the network after a transition that began on June 4 and carried into June 5.

The distinction between those dates matters. The network’s version 3.0.0 release was published on June 4, and node operators were warned that older software would no longer interact with the upgraded network beginning June 5. Mina’s June 7 announcement marked the project’s formal statement that the broader upgrade process had been completed; it was not the first Berkeley block or the start of the network transition.

The development was consequential because Mina had spent roughly three years preparing to move from a specialized, recursively proved blockchain toward a programmable application platform. Completion made the protocol’s zkApp transaction logic available on mainnet, but it did not demonstrate application adoption, commercial demand or sustained performance under heavy use.

What Berkeley changed

The upgrade incorporated three community-approved Mina Improvement Proposals. Together, they introduced zkApp programmability, replaced the earlier proof system with the more capable Kimchi system and removed the temporary “supercharged rewards” mechanism that had favored certain staking participants during the network’s early growth.

For developers, the central feature was the ability to write zero-knowledge smart contracts using o1js, a TypeScript-based library, and deploy them through Mina’s mainnet tooling. The model performs application computation away from the base chain and submits cryptographic proofs for verification on-chain. That can keep private inputs or large computations outside the public ledger while still allowing a contract to verify that specified rules were followed.

Off-chain execution does not make computation free in an economic sense. Someone must still generate the proof, operate application infrastructure and submit transactions. Privacy is also optional and application-dependent; Mina’s transparent base layer did not automatically make every transaction or zkApp confidential.

A coordinated network transition

The upgrade required operators to install the mandatory 3.0.0 Berkeley software. The official release identified Git commit `93e02797f72abe2cbf8dfca6f2328e9c8cd76546` and supplied packages for the Mina daemon, archive node and Rosetta interface.

Pre-upgrade documentation warned users to expect approximately 15 hours during which transactions would not be accepted while the network state was exported, migrated and restarted. That figure described the planned transition window, not a verified measurement of the realized outage. The June 7 issuer announcement credited more than 400 node operators with participating in the transition, but it did not publish an independently reproducible count or a detailed availability report.

Mina also continued to describe its recursively proved chain representation as approximately 22 kilobytes. That claim referred to the succinct proof used to verify the chain’s state history; it did not mean all raw transactions, archive data or application state occupied only 22 kilobytes. Archive operators still maintained substantially larger databases.

What completion did—and did not—establish

By June 7, Berkeley had moved zkApps from test networks into Mina’s production protocol and supplied developers with a defined mainnet release. It also demonstrated that a community-governed upgrade combining consensus, proof-system and reward changes could complete its coordinated rollout.

The event-day evidence did not establish that zkApps were secure by default, that users would adopt them or that Mina could support unlimited practical throughput. Each application still required its own design, testing and security review, while network performance depended on proof generation, transaction capacity, tooling and operator behavior.

The defensible June 7 conclusion is therefore narrower than the project’s promotional language: Mina completed and formally announced a major programmable-ZK upgrade, creating new mainnet capabilities whose real-world use and operational limits remained to be tested.