Zcash NU7 upgrade to disable v4 transactions for Sprout pool

The upcoming Zcash Network Upgrade 7 (NU7) will disable v4 transaction formats, effectively rendering ZEC held in the legacy Sprout privacy pool unspendable. While the funds will remain visible on the ledger, the network will no longer accept the v4 transaction type required to move assets out of the Sprout pool. Users holding funds in legacy zc... addresses or those using early desktop wallets are advised to migrate their assets, as newer v5 and v6 transaction formats do not support Sprout withdrawals.