Zcash confirms NU7 testnet activation as mainnet decision approaches

Zcash's next network upgrade is running on its public testnet, with the production rollout still awaiting a final activation decision. An October 6 engineering update from the Zcash Foundation confirms that NU7 activated at testnet block 4,465,026 on October 4.

The official Zcash account also announced the testnet activation on October 4. The milestone gives developers a live environment to check changes to block timing, miner payments and transaction handling before applying them to the main network.

NU7 cuts the interval between blocks from 75 seconds to 25. The amount of ZEC issued each day remains unchanged, because the subsidy paid with each block adjusts to the faster schedule. More frequent blocks therefore do not mean a tripling of new coin issuance.

The upgrade also introduces a fee reserve. Sixty percent of each block's transaction fees is set aside and paid to miners gradually through future blocks. Alongside that change, NU7 limits shielded activity within each block to help protect light wallets against spam and retires the older version-four transaction format.

CoinPost's October 6 report describes the testnet launch and the faster block schedule. The Foundation's update supplies a firmer boundary around the production timetable: no mainnet activation height has been set. The published planning thread calls for a final decision on October 20, following testnet experience, and targets November 5 for activation. That remains a target.

There is a separate, immediate software issue for node operators. The Foundation says mainnet operators do not need to make an NU7 change yet, but should be running Zebra 6.4.2. That release fixed a crash that a malformed transaction from any network peer could trigger, discovered by Google's OSS-Fuzz testing service.

The NU7 release candidate, Zebra 7.0.0-rc.0, is part of the testing work. Its database upgrade cannot be reversed by simply returning to an older Zebra version, and tools that read the database directly need compatible releases. Those constraints make compatibility testing important before a production migration.

The next checkpoint is the mainnet decision. The Foundation expects a mainnet release before the existing Zebra 6.4 series reaches its expiry in early November; the testnet launch establishes progress toward that release, while leaving its activation timing unsettled.