zakura

Release: Zakura 1.6.0

We have released Zakura 1.6.0. This release activates NU7 on Testnet at height 4,465,026, expected around October 6.

Performance has been a focus of our last several releases: blocks now verify 8× faster on average and 17× faster when full of transactions. With NU7 set to triple the rate of block production, the speed of processing full blocks matters more than ever.

We recommend that all node operators update.

NU7 Is in the Release

Zakura 1.6.0 includes the full implementation of the upcoming NU7 network upgrade: 25-second blocks, shielded action limits, and the Network Sustainability Mechanism. This release supports activation of NU7 on Testnet at height 4,465,026.

Mainnet activation is not yet scheduled. Follow the NU7 Dashboard for rollout status.

The work behind this upgrade began well before activation. Our 80-node stress test, spread evenly across 11 regions, mined blocks full of shielded transactions at 25-second spacing: three times the current Mainnet rate. We have continued to reduce processing and propagation delays since then.

Lower Fees

Zakura's conventional fee falls from 5,000 to 400 zatoshis per logical action, applying to mempool admission, eviction, and mining template selection. The template fee-weight cap also rises from 10 to 13, so transactions paying the old rate keep their full weight. This deliberately departs from ZIP 317; it changes relay and mining policy, not consensus.

Faster Verification, Gossip & Sync

  • Blocks verify faster. Equihash verification and the optional CPU miner now use the faster pure Rust implementation in Common, our cryptography stack for Zcash. Sapling proof verification is faster as well, and transaction verification spends less work detecting duplicate inputs and nullifiers.
  • Chain state updates and rollbacks copy less. Snapshots share unchanged output indexes, address indexes, and retained block records, and block tracing avoids formatting entire blocks and UTXO maps.
  • Committed blocks are gossiped immediately. Previously, a block could wait up to seven seconds after the last block gossip, a delay that matters more as block intervals get shorter. Transaction gossip batches also run every two seconds instead of seven.
  • Our experimental P2Pv2 stack syncs leaner and stricter. Header lookahead keeps work available before the block backlog drains, checkpoint processing does less repeated work, and block downloads reserve advertised or known body sizes instead of budgeting the full 2MB for every block. Stream frames are checked before their payloads are read, response allocations and serving queues are bounded, and block responses preserve the requested order.

Other Changes

  • Common is updated to 2.2.0, carrying the Testnet NU7 activation schedule.
  • Published x86-64 binaries run on CPUs without BMI2 or ADX. Building locally with -C target-cpu=native enables the faster Pasta field arithmetic automatically.
  • Sentry reporting is opt-in. Enabling it requires a build with --features sentry and a runtime SENTRY_DSN.
  • The database format advances to 29.1.0, without a migration.
  • Public Mainnet and Testnet configurations now reject legacy testnet_parameters overrides. Remove those overrides before upgrading; custom Testnets remain configurable through the explicit network = { ... } form.

End of Support

Mainnet zakurad nodes running 1.6.0 halt at height 3,536,467 (estimated 2026-11-01); upgrade warnings begin three days earlier.

Updating

You can update using our signed release binaries or by upgrading the zakura crate to 1.6.0 via Cargo. See the download page for installation and verification instructions.