Zcash NU7 mainnet height wins two approvals, putting 25-second blocks on track for around Nov. 5

Zcash (ZEC) developers have proposed mainnet block 3,543,405 as the activation height for NU7, the network's next upgrade. Zcash developer Sean Bowe opened a change to the zcash/zips repository, which holds Zcash's protocol rules, on Oct. 19 U.S. time, and two ZIP editors approved it on Oct. 20. At the current pace of one block every 75 seconds, the chain would reach that height around Nov. 5.

ZIPs are Zcash Improvement Proposals, and ZIP editors are the people who review and approve them. The pull request says: "Height agreed at ZIP editor meeting." As of Oct. 21 afternoon KST, the change had not been merged, and the published deployment document, ZIP 259, still listed the mainnet height as "TBD (To be set on OCT 20)." One of the approvers, str4d, commented: "The next work to do is to transition all NU7 ZIPs to Proposed."

Testnet went first in early October; mainnet targets block 3,543,405

NU7 is already live on testnet. Zebra, the Zcash Foundation's node software, released 7.0.0-rc.0 for testnet on Oct. 2 and said the testnet activation height of 4,465,026 was "expected around October 6th." That release set no mainnet height, and it said mainnet node operators were not required to upgrade. The timeline so far:

As of 5:30 p.m. KST on Oct. 21, Zcash mainnet stood at block 3,525,333, about 18,000 blocks short of the target.

Blocks every 25 seconds, with 60% of fees set aside

The biggest change is block spacing. ZIP 259 says "NU7 reduces the block target spacing from 75 seconds to 25 seconds." ZIP 218, which specifies the new spacing, says that for users who wait for one or two confirmations and for small payments, "the user-visible latency goes down 3x." Because blocks will come more often, NU7 also adds new caps on shielded throughput (the number of actions) each block can hold.

Fee handling changes too. Sixty percent of transaction fees will be removed from circulation and held by the Network Sustainability Mechanism (NSM), and miners will receive the remaining 40% right away. The set-aside amount will be released gradually on top of block rewards starting at mainnet height 8,939,664, which works out to around February 2031 at 25-second blocks. ZIP 259 says the changes "do not increase the ZEC supply cap." The halving schedule stays in place.

Sprout coins must move before early November

Once NU7 activates, version 4 (v4) transactions become invalid. Withdrawals from Sprout, Zcash's original shielded pool, can only be built as v4 transactions, so ZIP 259 states that "funds remaining in the Sprout pool become unspendable." Users holding ZEC at Sprout addresses need to move it to another pool before activation.

Zcash is not listed on the Korean won markets of Upbit, Bithumb, Coinone or Korbit. At 5:30 p.m. KST on Oct. 21, ZEC traded at $1,273 on Binance, up 13% from 24 hours earlier. The funding rate on Binance's ZEC perpetual futures stood at 0.0068% at the same time.