- NU7 reduced Zcash’s target block interval from 75 seconds to 25 seconds.
- The Network Sustainability Mechanism will direct 60% of transaction fees from each block to a public reserve.
- The upgrade disabled version 4 transactions, leaving about 12,224 ZEC in the legacy Sprout shielded pool unspendable.
The Zcash (ZEC) team activated the NU7 network upgrade on Nov. 5 at block height 3,543,405. The upgrade cut the target block interval from 75 seconds to 25 seconds, introduced a mechanism for reserving transaction fees and ended support for the transaction format used by the legacy Sprout privacy pool.
To maintain the existing pace of ZEC issuance, the upgrade reduced block subsidies to one-third of their previous level. It also tripled the number of blocks between halvings, preserving the existing reward-reduction schedule and the capped supply of 21 million coins.
Transaction fees and mining changes
NU7 introduced the Network Sustainability Mechanism, or NSM, which will direct 60% of the transaction fees from each block to a public reserve. Miners will receive the remaining 40%.
The reserved funds are expected to return gradually to circulation through block rewards beginning at block 8,939,664. Current estimates place that milestone around 2031.
Shielded Labs, an independent organization that supports Zcash development, said the mechanism should help maintain network security as block rewards decline while allowing the supply cap to remain at 21 million ZEC.
The upgrade also changed Zcash’s mining difficulty adjustment mechanism by increasing its averaging window from 17 blocks to 102 blocks.
Sprout funds become unspendable
NU7 ended support for version 4, or v4, transactions. Because the legacy Sprout shielded pool uses only that format, coins remaining in the pool when the upgrade activated became unspendable. The pool held about 12,224 ZEC at the time.
Sprout is Zcash’s oldest shielded pool and allows users to conceal the sender, recipient and transaction amount. It launched with the Zcash network in October 2016, but newer technology later replaced it for private transfers.
Node operators had to update their software before NU7 activated to remain on the consensus network. Most wallet users do not need to make significant changes.
Grayscale previously suggested that Zcash’s share could continue to grow relative to bitcoin.
Source: Incrypted
