Zcash will undergo a major network upgrade called "Network Upgrade 7" (NU7) on November 5, which will reduce block times from 75 seconds to 25 seconds. This upgrade will also disable Sprout transactions, and users are advised to migrate funds from the Sprout pool to the Sapling pool before then. Additionally, NU7 introduces a network sustainability mechanism that recycles a portion of transaction fees into future block rewards and adds new shielding limits to protect wallets from spam attacks. Zebra 7.0.0 has been released to support this upgrade.