Aztec, the privacy-focused Ethereum layer-2 network, has rolled out a major upgrade that fixes a critical vulnerability from its previous version, doubles the speed of private transactions, and ushers in a wave of applications built to keep user data hidden. The Aztec Foundation said Tuesday that the upgrade, called Aztec Tierra and designated Alpha V6, delivers stronger security, formal verification of its proving system and faster deposits from Ethereum, alongside a refreshed brand.