Zcash executed its NU7 network upgrade on Friday, rendering approximately $15 million in ZEC tokens held within the legacy Sprout shielded pool unspendable. The change took effect at block 3,543,405 at 02:34 UTC, according to the blockchain analytics platform ZecStats, which recorded the Sprout pool balance at about 12,224 ZEC.
Sprout pool funds frozen
The upgrade enforces the rules outlined in Zcash Improvement Proposal 2003, which directs the network to reject version 4 transactions. This is significant because version 4 is the only format that permits the movement of Sprout-based coins. As a result, users can no longer transfer the affected funds under the new network protocols, although the coins have not been destroyed or removed from the total supply.
The project’s documentation clarifies that there remains a possibility, however uncertain, for access to these coins to be restored through future network changes. For now, their use is effectively suspended unless later upgrades allow version 4 transactions once again or introduce a different access mechanism. Still, developers caution that this restoration may never occur.
The specification leaves open the possibility that a future network upgrade could restore access, but also warns that “the ability to spend Sprout funds may never be re-enabled.”
Block timing and sustainability updates
Alongside the Sprout pool lockout, NU7 adjusts the network’s target timing for blocks, cutting the average interval from 75 seconds to 25 seconds. As mining difficulty shifts, actual block production will gradually conform to the new target.
The upgrade also activates the Network Sustainability Mechanism, a new protocol component. This mechanism removes 60% of transaction fees from circulation, earmarking them for eventual redistribution as mining rewards beginning around February 2031.
Zcash’s overall structural features remain unchanged, including the fixed maximum supply of 21 million ZEC and the established halving cycle. NU7 additionally introduces limits on shielded transaction activity, which is intended to ease wallet synchronization and improve network efficiency for users.
Implications for Zcash users
As the $15 million in ZEC within the Sprout pool is now inaccessible, investors and holders must focus on newer shielded pools or transparent ZEC addresses to transact on the network. The adjustment of block intervals and the shift in transaction fee handling also mark major changes that participants need to monitor for their potential impact on network activity and ZEC economics.
To keep pace with these network changes, traders and holders seeking real-time monitoring of Zcash’s activity can make use of CryptoAppsy’s dynamic charting tools and instant coin-specific news feeds. These features can help users track the effects of the new NU7 mechanisms and promptly spot major movements in ZEC liquidity or fee distribution as the network adapts.
NU7 also introduces a Network Sustainability Mechanism that removes 60% of transaction fees from circulation for eventual reissuance through future mining rewards, starting around February 2031.
Zcash continues to face governance discussions, as highlighted by the Zcash grants group’s recent $124 million compromise proposal amid community debate.
