Program Upgrade
Programming Model · Deep
Deploying new bytecode to an existing Solana program address via the Upgradeable BPF Loader. The program's public key and all derived PDAs remain unchanged — only the executable binary is replaced. Requires the upgrade authority (a designated signer) to approve. This enables shipping fixes without breaking integrations, but a compromised authority can silently replace program logic. Programs can be made immutable by setting the upgrade authority to None.