Legacy Sprout Pool Funds Face Potential Lock-Up in Zcash's Upcoming NU7 Upgrade
Version 4 transactions would be disabled under the proposed NU7 change, making ZEC tokens stored in Zcash's older Sprout shielded pool unable to be spent.
Holders of ZEC tokens within Zcash's older Sprout shielded pool need to transfer their assets prior to the forthcoming NU7 upgrade to avoid permanently losing access to their funds.
According to Zcash Improvement Proposal-2003, the NU7 implementation would discontinue support for the legacy transaction format that enables spending from Sprout addresses. Any ZEC remaining in this pool following the upgrade would no longer be accessible for transactions.
While the proposal does not include burning the Sprout funds and maintains the potential for future access restoration, it cautions that token holders might permanently lose the ability to spend assets that remain in the pool.
On Sunday, a Zcash Community Forum participant using the handle "vaspholdings" issued an alert encouraging ZEC token holders to examine their older wallets ahead of the upgrade. According to the user's post, these wallets could hold Sprout ZEC, transparent ZEC, or a combination of both. The proposed limitations would exclusively affect funds stored in the Sprout pool.
Zooko Wilcox, one of Zcash's co-founders, amplified the cautionary message through his X account.
The NU7 upgrade has a scheduled testnet activation date of Oct. 6. The Zcash team plans to make a final determination on Oct. 20 regarding whether to move forward with the planned Nov. 5 mainnet deployment.
Beyond the transaction format changes, the upgrade would also reduce Zcash's target block time from its current 75 seconds down to 25 seconds. The proposed modifications to the issuance mechanism are designed to maintain the network's existing halving schedule.
At the time of writing, ZEC was trading at $1,627.82, representing an 8% increase over the previous 24 hours and approaching a 40% gain for the past week, based on data from CoinGecko.