The Zcash Foundation has released Zebra versions 4.5.3 and 5.0.0 to address a critical vulnerability in the Orchard zero-knowledge proof circuit. Version 4.5.3 implements an emergency soft fork to temporarily disable Orchard operations, ensuring network security. Meanwhile, version 5.0.0 activates Network Upgrade 6.2, re-enabling Orchard with a patched circuit to permanently resolve the issue.