Zcash's NU7 upgrade will freeze about 12,224 ZEC left in Sprout pool

Key points

• About 12,224 ZEC, worth roughly $15m to $16m, remains in the Sprout pool, according to ZecStats data updated on 5 November.
• NU7 activates at block 3,543,405, expected on Thursday evening in the United States, and makes v4 transactions invalid.
• The upgrade cuts Zcash's target block interval from 75 seconds to 25 seconds, so transactions confirm about three times faster.

Zcash's NU7 upgrade will freeze about 12,224 ZEC held in Sprout, the network's original privacy pool, unless owners move the coins before activation. ZecStats data updated on 5 November put the remaining balance at roughly $15m to $16m at recent prices. The upgrade is due at block 3,543,405, expected on Thursday evening in the United States, with the exact time set by block production rather than a clock.

Sprout introduced Zcash's zero-knowledge privacy technology when the network launched in 2016. Later systems, including Sapling, Orchard and Ironwood, replaced it, and Sprout has been closed to new deposits for years, though existing holders could still withdraw. NU7 removes version-4 transactions, the only format able to move coins out of Sprout, so what remains becomes frozen rather than burned, according to ZecStats.

The coins are not technically destroyed. They will still count toward Zcash's circulating issuance, and a future upgrade could in theory restore access, though the specification warns that spending may never be re-enabled. The blockchain cannot show who owns the remaining balance, so it is unclear how much belongs to active users and how much is already lost with keys.

Users of modern wallets need not migrate.

What to watch: NU7 activates at block 3,543,405, expected on Thursday evening in the United States, after which any ZEC left in Sprout is frozen.

Read the full story on Decrypt →