Zcash sets NU7 activation for block 3,543,405

Zcash users should see the average wait for a first transaction confirmation fall from 75 seconds to 25 once the NU7 upgrade activates, planned for around Nov. 5 at block 3,543,405. The Zcash Foundation’s Zebra 7.0.0 release announcement confirms the activation height and says NU7-supported software is available.

The shorter block interval can speed up services that wait for confirmations, but users with funds in the old Sprout pool need to act before activation.

NU7 changes how often Zcash adds a block, the batch of transactions recorded together. The first confirmation is expected about three times sooner on average; the change does not mean every transfer is final in 25 seconds, since exchanges and other services may wait for multiple confirmations before crediting a deposit.

For example, CoinDesk reports that a service waiting for three confirmations could see the delay drop from nearly four minutes to about 75 seconds. Actual crediting times will depend on each service’s policy. The upgrade has been running on Zcash’s public test network, and the planned activation date remains an estimate tied to the block height.

What do Zcash users need to move before NU7?

Anyone with funds in Sprout, Zcash’s original privacy pool, should move them before NU7 activates. The CoinDesk report on the activation proposal says Sprout will shut down, leaving any funds still there unspendable; those transfers can only use version 4 transactions, which NU7 will no longer accept.

NU7 does not add new transaction formats: versions 5 and 6 remain valid, according to the Foundation’s release. The release does not announce a new user fee for the faster blocks. It does say 60% of each block’s transaction fees will go into a reserve, while miners keep 40%; a portion of the reserve is scheduled to return through future block rewards.

Do node operators need to update?

Yes. The Foundation says all mainnet node operators must upgrade before block 3,543,405 to stay on the consensus chain. Zebra 7.0.0 is the first stable Zebra release with NU7 mainnet support; after activation, nodes running older versions will be disconnected by NU7 nodes and follow a different chain.

Wallet users who do not operate a node have a more immediate check: whether they still hold Sprout funds. Exchanges and other services may also need to account for the shorter confirmation interval when deciding when to credit deposits, while the exact time a user can spend a received payment remains subject to that service’s own confirmation rules.

Source material

• Zebra 7.0.0 release announcement — forum.zcashcommunity.com
• CoinDesk report on the activation proposal — coindesk.com