Zcash NU7 Upgrade Launches on Testnet Ahead of November Mainnet Rollout
Zcash has activated its NU7 network upgrade on the public testnet, marking a significant step toward faster block times and improved transaction efficiency. The upgrade went live on October 4 at 18:21:45 UTC when block 4,465,026 was mined on the Zcash testnet. The NU7 upgrade aims to reduce block spacing from 75 seconds to 25 seconds, which is expected to enhance transfer times for payments, deposits, and cross-chain transactions.
One of the key features of NU7 is the Network Sustainability Mechanism, which redirects 60% of transaction fees into a reserve account to fund future emission costs. This adjustment ensures that the issuance rate remains stable despite the increased frequency of blocks. Additionally, NU7 disables version 4 transactions, affecting ZEC held in the legacy Sprout shielded pool. Holders of these funds are urged to move them before the mainnet activation to retain the ability to spend them.
Zcash developers have scheduled a final decision on mainnet activation for October 20, with the target date for the upgrade set for November 5. The testnet phase allows network participants and infrastructure providers to test the upgrade under real network conditions. The Zcash Foundation has encouraged testnet operators to deploy the release candidate and conduct thorough testing.
The NU7 upgrade also introduces restrictions on shielded transactions in each block, aiming to improve shielded transaction capacity and reduce the potential verification load from spam transactions on lightweight wallets. The upgrade was confirmed in a post on X, and Zcash has emphasized the importance of moving funds from the Sprout shielded pool before the full activation of NU7.