Midnight Ledger 9 Hard Fork Brings Private Asset and Stablecoin Transfers

Midnight (NIGHT) upgraded its mainnet from Ledger 8 to Ledger 9 in a hard fork that activated on November 6, 2026, according to the project's docs and release notes. The upgrade adds privacy-focused asset and stablecoin transfers, new smart contract features and a rebuilt cryptographic proving stack. It is the first full release of the ledger-9 line, the codebase built for this hard fork.

What the Ledger 9 Hard Fork Changes

The hard fork applies an on-chain runtime update that moves the chain to ledger version 9.1.0.1. Midnight describes the upgrade as an expansion of mainnet capabilities, covering new cryptographic tools, privacy-focused transfers of assets and stablecoins, and additional smart contract features. The project's release notes list everything shipped across the 9.1.0.0 release candidates that fed the fork.

A New Proving Stack and ECDSA Signatures

The headline change is the move to midnight-zk-stdlib v2 and midnight-circuits v7 for generating and verifying zero-knowledge proofs. Proofs made with the older zk-stdlib v1 remain verifiable, and Zswap shielded transfers keep accepting v1 proofs. Ledger 9 also adds support for zkir v3 circuits and for ECDSA signatures, so contracts can work with the signature scheme used across Ethereum-compatible tooling.

Transaction costs change as well. The ledger now has an explicit price floor, and the old parallelism factor is replaced by separate cost factors for validation, guaranteed application and fallible application. A new UnlockToTreasury system transaction moves funds from the locked pool to the network treasury.

What Developers Need to Update

Contract developers face one breaking change: verifier keys generated with the old stack are superseded by v3 keys under ContractOperationVersion::V4. Maintenance updates can now insert and remove contract operation code directly on chain, and contracts gain an on-chain event log format. The ledger-9 packages are also published for the first time on crates.io and npm, including the new midnight-ledger-v9 crate.

Security Fixes Carried into the Fork

Ledger 9 includes the security fixes previously released to mainnet as versions 8.1.2 and 8.1.3, mainly hardening low-level data deserialization across the serialization, storage and virtual machine libraries. Encodings that are not canonical and values that break their type rules are now rejected.

Midnight is a privacy-focused blockchain in the Cardano ecosystem, listed in Coinranking's privacy coins and zero-knowledge proofs categories. Market reaction to the fork is visible on the Midnight price chart on Coinranking.