Cardano Set September 22 for Its Delayed Vasil Upgrade

Cardano set a date for Vasil

On September 2, 2022, Input Output Global, the development company then commonly identified as IOG, announced that Cardano’s Vasil upgrade was scheduled for September 22, 2022. The company said the date followed completion and testing of core components and a joint readiness assessment with the Cardano Foundation.

The development was a scheduling decision, not the hard fork itself. Cardano’s mainnet was still running its pre-Vasil protocol on September 2. That distinction mattered because Vasil had already moved beyond an earlier June target, and because a protocol release depends on more than finished code: stake-pool operators, exchanges and decentralized applications also had to update and test their integrations.

Contemporaneous reporting by CoinDesk confirmed the September 22 schedule on September 2 and described the release as a delayed scaling upgrade. The same report said Vasil was intended to expand Cardano’s capacity and reduce transaction costs, but those were design objectives on the announcement date, not measured production results.

Readiness was an ecosystem test

IOG framed the decision around three project-defined “critical mass” indicators. It reported that at least 75% of mainnet blocks were being produced by the final Vasil node candidate, version 1.35.3; roughly 25 exchanges representing about 80% of ADA liquidity were expected to be upgraded; and the ten largest Cardano decentralized applications by total value locked were being checked for readiness on the pre-production environment.

Those figures should be read as contemporaneous IOG readiness claims. The surviving announcement and reports do not provide a neutral audit, a complete venue-level liquidity calculation, or a fixed observation window from which an outside reader could reproduce every percentage. They nevertheless show why September 2 was consequential: Cardano’s developers believed enough of the network’s operational perimeter had aligned to start a mainnet countdown.

The coordination model also narrowed what “hard fork” meant in this case. Cardano planned to use its hard fork combinator to move the ledger to new protocol rules while preserving chain continuity. The September 2 announcement did not establish that every exchange, wallet or application was ready, and it did not guarantee an interruption-free transition.

What the upgrade was meant to change

Vasil was presented as a performance and smart-contract upgrade. The Cardano Foundation’s technical account, published on September 7, described changes to Plutus script handling and three Cardano Improvement Proposals: CIP-31 for reference inputs, CIP-32 for inline datums and CIP-33 for reference scripts. In practical terms, those changes were intended to let applications reuse or read on-chain data and scripts with less duplication, potentially reducing transaction size and script-execution overhead.

That September 7 explanation is later context, not evidence that the features were live on September 2. Developers and users still faced integration work, and lower resource use in particular transaction designs did not promise lower fees for every transaction or greater application demand.

Later confirmation

Cardano’s official protocol history records that Vasil activated on September 22, 2022, at epoch 365 as protocol version 7.0. That later record confirms that the announced date was ultimately met. It should not be projected backward: the verifiable development on September 2 was the commitment to a date after a reported readiness review, while actual mainnet activation remained a future, technically contingent event.