Midnight said in its November 6 mainnet announcement that Mainnet had moved from Ledger 8 to Ledger 9. The upgrade adds native support for ECDSA signatures and Keccak hashing, compatibility with BIP-44 wallet paths, cross-contract execution and public contract events. It also requires developers to update to Midnight.js 5 and the new Compact toolchain.
The rollout was completed across the other public environments over the following three days. Midnight’s release overview records that Mainnet upgraded on November 6, Preview relaunched on November 7, and Preprod upgraded in place on November 9. All three now run Ledger 9.1.0.1.
That sequence matters because Ledger 8 is no longer the target for public development. Applications, wallets and infrastructure that still depend on the older ledger version must align with the new transaction, tooling and proof requirements. For builders, this is not only a contract-language update. It reaches into Midnight.js, wallet software, indexers, proof servers and deployment workflows.
The Ledger v9.1.0.1 release notes describe the breaking changes in more detail. Ledger 8 transactions are rejected, while upgrades are required for Midnight.js, the Wallet SDK, indexers and proof servers. The release also introduces ZKIR 3, alongside the new cryptographic capabilities, and requires indexers to be reindexed. The notes identify known migration issues, making the transition a practical infrastructure project rather than a simple node restart.
The most important additions are aimed at making contracts easier to connect to existing cryptographic and application systems. ECDSA support can help applications work with widely used signature schemes, while Keccak and BIP-44 compatibility reduce friction for wallet and interoperability tooling. Cross-contract execution provides a foundation for composable applications, and public events give contracts a standard way to expose activity to off-chain services.
The migration also carries a concrete operational risk. In a GitHub issue, Midnight.js contributor sp-io reported a Ledger 9 deployment failure mode in which a failed local store write could result in the loss of a contract’s maintenance key. That criticism points to the part of the rollout that developers cannot assess from feature lists alone: whether deployment tooling handles partial failures safely.
The material reviewed for this report contains that critical view, but no opposing response was identified. The broader test for Ledger 9 is therefore ecosystem coordination. If wallets, indexers, proof infrastructure and application frameworks update together, the new ledger can provide a cleaner base for composable contracts. If they do not, users may encounter incompatible wallets, incomplete indexing or failed deployments even though the underlying network upgrade is complete.
Noah Brown is not a person. No notebook, no deadlines, no face behind the name — just a byline this newsroom publishes under. Here is the production line underneath it, because a name beside a portrait reads like a journalist, and this one is not one.
The models. Writing: gpt-5.6-luna and gpt-5.6-terra. Out on the live web: gpt-5.6-terra and gpt-5.6-luna. Pictures: gpt-image-1 and flux. Swap one in the newsroom and this line swaps with it — it is read off the machines, not typed here.
How a story is made
- Research. The searching model reads around the story, pointed at primary sources — the filing, the post, the repository — rather than at somebody else's write-up of them.
- Writing. The writing model drafts it against what was found, at Noah Brown's usual length and in Noah Brown's usual register.
- The loop. A reviewer reads the draft and sends it back with notes. Then reads it again. A piece can go round several times before it leaves the building.
- Enrichment. A quotation has to appear word for word on the page it is taken from. A chart may only use figures that appear in the source it cites. Whatever fails is dropped, and the reason is kept.
- Fact check. A last pass hunts for claims the article makes and its sources do not.
- A human stop. Sensitive subjects are held for a person to read before publication, and a person can kill any of it at any point.
If that sounds less like a newsroom and more like a factory: quite. It is called Press Factory.
This article was generated using AI and published automatically without human pre-publication review.
How this article was made
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