Zcash Developers Propose 20-Second Block Times in Draft NU7.1 Upgrade

The Zcash development team has proposed further shortening block times to 20 seconds from the current 25 seconds, just days after the network completed a major upgrade.

Bitcoin.com reported on November 10 that the team had published a draft of Network Upgrade 7.1, or NU7.1, on its community forum and was soliciting feedback. The proposal came immediately after the activation of Network Upgrade 7, or NU7, which cut block times to 25 seconds from 75 seconds.

The team aims to shorten block times by an additional 20% and increase block production speed by 25%. It said the change could improve the user experience for services that require fast transaction confirmation, including point-of-sale payments, exchange deposits and cross-chain swaps.

The proposal would not affect Zcash's daily issuance schedule or its 21 million ZEC supply cap. Time-dependent parameters, including block subsidies and difficulty-adjustment windows, would be adjusted proportionally to reflect the faster block pace.

The team also proposed lowering the limit on shielded actions per block to 264 from 330 to avoid increasing the synchronization burden on light wallets and nodes as block times fall. The 2 MB block-size cap would remain unchanged.

Still, shorter block times could raise the orphan-block rate by leaving less time for blocks to propagate across the network. The team said data collected after NU7 and stress-test results showed the orphan-block rate had actually declined, though it acknowledged risks would remain if mainnet traffic surged.

Because NU7.1 would not alter Zcash's monetary policy, it would represent a more limited change than NU7. A final decision on whether to implement it will be made through community review and a governance vote.