TL;DR:
The engineering team at o1Labs published a detailed update on the status of Mesa, the next major protocol upgrade for the Mina network. The report documents the work carried out over the past month on the testnet, launched in November 2025 as an intentionally unstable pre-production environment, designed to detect issues early and lay the groundwork for a safe migration to mainnet.
Among the most significant advances, the team completed nine upgrade rehearsals across different modes, configurations and architectures. Rehearsals 7 and 9 were corporate-scale, involving participants from multiple time zones and varying levels of experience to simulate a realistic upgrade scenario. During these tests, a glibc dependency issue was identified and resolved, and a bug preventing nodes from starting correctly under certain conditions was fixed.
One of the most notable achievements of the period was the optimization of the packaging pipeline, which reduced package generation time from two hours to just 22 minutes. The team also developed a real-time monitoring tool that allows users to visualize what percentage of active stake has migrated to the new version, and launched a dedicated explorer with a full history of blocks and transactions for all networks associated with Mesa.
At the protocol level, the OCaml workstream completed the automatic upgrade mode for the hard fork, a substantial improvement over the manual process used in previous versions. The average block time on the Testnet was also corrected, and a persistent memory leak in the Mina daemon linked to the libp2p auxiliary code was resolved.
On the application development front, the team launched a preview version of o1js 3.0, which provides complete tooling for developers. The end-to-end migration pipeline was also completed to upgrade zkApps from Berkeley to Mesa, with successful tests of the upgrade mechanism carried out during recent rehearsals.
The next stage of the process is Trail, which will start from a state similar to Berkeley’s and execute a full upgrade replicating exactly what will happen on mainnet. Prior to its launch, a final rehearsal will be conducted after the code freeze. Simultaneously, the Trailblazers program will be launched, an initiative offering incentives for experienced node operators, selected to represent diverse geographies, hardware configurations and deployment environments.
