Zcash activated the NU7 network upgrade on its testnet on October 4 at block 4,465,026 (18:21:45 UTC), giving developers several weeks to evaluate 25-second blocks and other changes ahead of the planned mainnet activation in November.

NU7 reduces block interval and disables v4 transactions

The upgrade lowers the target pause between blocks from 75 to 25 seconds, disables version 4 transactions, and introduces the Network Sustainability Mechanism, which redirects a portion of fees into future block rewards.

Funds in the Sprout ZEC pool may become inaccessible

Disabling v4 transactions will leave ZEC funds in the legacy anonymous Sprout pool unspendable unless users transfer them before full NU7 activation.

Mainnet decision on October 20, launch target is November 5

Zcash developers plan to make a final decision on NU7 mainnet activation on October 20 and set the activation height based on testnet results. The target date for mainnet activation is November 5. The Zcash Foundation has urged testnet operators to use the release candidate to test NU7 "under real conditions."