Zcash's NU7 puts a tentative Nov. 5 deadline on ZEC left in Sprout

Testnet's activation block arrived about two days ahead of the roughly Oct. 6 date developers had estimated ^[2][6], and a mainnet height can drift from its intended date the same way. A Sprout holder who waits for the Oct. 20 decision and then plans around Nov. 5 has 16 days ^[7][1], and that is before allowing for any drift.

Spending from Sprout relies on version 4 transactions ^[5]. NU7 disables them at mainnet activation ^[4], and it introduces no new transaction formats ^[9]. Crypto.news and Cointelegraph both report that ZEC left in Sprout would become unspendable ^[4]. CoinDesk's wording is narrower: it writes that holders would need to move funds before activation "to retain the ability to spend them through the existing system" ^[8]. The reports do not say how much ZEC remains in Sprout, and they do not describe any way to recover it after activation.

The developers left the total supply alone. A day has room for 1,152 blocks at the current spacing and 3,456 under NU7 ^[2]. With the per-block reward cut to one-third ^[11], the faster chain pays the same daily subsidy as the slower one ^[3]. The halving schedule also stays, backed by about 98.9% of the coins polled ^[13].

The testnet will go through a supply event of its own before the review. Its adjusted third halving is set at block 4,497,948 ^[15], which is 32,922 blocks after activation. At the 25-second target those blocks take about nine and a half days to mine, putting the halving around Oct. 14, six days before developers decide ^[5]. CoinDesk notes that actual block times vary ^[22].

Oct. 20 can go three ways. If developers set a height consistent with Nov. 5, Sprout holders get their 16 days ^[1]. If testing turns up a fault in the fee rules, or in the new limits on shielded actions meant to protect wallets from spam as blocks come faster ^[20], the height moves out and holders get more time. Or developers aim a height at Nov. 5 and it lands days away, as the testnet's did ^[6].

I'd expect the first. The Zcash Foundation, Project Tachyon, Valar Group, ZODL and Shielded Labs agreed the scope unanimously after polling coinholders ^[16]. The foundation also told testnet operators to run its release candidate and test NU7 "under real conditions" ^[18]. The case against is that testnet is the first live environment for these changes ^[23], and mainnet operators have been told they need not change anything yet ^[19]. If the Oct. 20 review sets a height that implies a date well after Nov. 5, or sets no height at all, the schedule was softer than that agreement suggested.