Zcash's NU7 Upgrade Goes Live on Testnet Ahead of November Mainnet Target
Key Takeaways
- •Zcash's NU7 network upgrade went live on testnet at block 4,465,026, mined on Oct. 4, roughly one month ahead of the targeted Nov. 5 mainnet launch.
- •The upgrade aims to reduce Zcash's target block spacing from 75 seconds to 25 seconds, meaning new blocks would arrive three times as often.
- •NU7 disables version 4 transactions, leaving ZEC in the legacy Sprout shielded pool unspendable unless holders move their funds before full activation.
- •A new Network Sustainability Mechanism redirects a portion of transaction fees into future block rewards, linking block reward funding to network fee activity.
- •Developers are scheduled to make a final decision on mainnet activation and set its activation height on Oct. 20 after evaluating NU7's testnet performance.
Zcash has activated its NU7 network upgrade on testnet, opening a several-week evaluation window in which developers will assess the upgrade's 25-second block times and other protocol changes before a targeted mainnet rollout in November.
The activation moves the planned protocol changes into live testing roughly one month ahead of the targeted mainnet launch, which is currently set for Nov. 5. Testnet activations allow protocol changes to be exercised in a live network environment without putting mainnet funds at risk.
Block 4,465,026 marks the activation point
According to ZecBlock, a block explorer for the Zcash testnet, block 4,465,026 — NU7's scheduled activation point — was mined on Oct. 4 at 18:21:45 UTC. Zcash confirmed the activation in a post on X, saying NU7 was live on testnet.
What NU7 changes
NU7 is Zcash's next network upgrade and seeks to reduce the network's target block spacing from 75 seconds to 25 seconds, meaning new blocks would arrive three times as often as they do now. The upgrade also disables version 4 transactions and integrates a Network Sustainability Mechanism that redirects a portion of transaction fees into future block rewards, linking future block reward funding to network fee.
As a result of the version 4 transaction deactivation, ZEC held in Zcash's legacy Sprout shielded pool would become unspendable unless users move their funds before NU7 fully activates, effectively creating a migration deadline ahead of full activation. The Sprout pool is the protocol's original shielded pool.
Final mainnet decision set for Oct. 20
The Zcash Foundation said on Friday that testnet operators should use the release candidate to test NU7 "under real conditions." The testnet phase allows developers to evaluate the upgrade's behavior in a live environment before deciding whether to proceed with mainnet activation.
Zcash developers are scheduled to make a final decision on mainnet activation and set its activation height on Oct. 20, based on their experience with NU7 running on testnet. The dates give the rollout a fixed structure: roughly two weeks of testnet evaluation between the Oct. 4 activation and the decision, then the same span between a green light and the Nov. 5 mainnet target should the upgrade proceed.
Related: Zcash gets a Washington lobbyist to push crypto policy
Source: Cointelegraph
