SIMD-0500 Will Block Making Old Programs Immutable

After SIMD-0500 activation, the Solana loader will stop freezing programs with old SBPF v0–v2 bytecode: the SetAuthority instruction with authority=none will fail. As of September 17, 2026, the rule is in the validator but not activated on mainnet. To renounce program rights, it must be rebuilt with a current toolchain, upgraded, and only then frozen.

• SIMD-0500 blocks deploy and upgrade of SBPF v0, v1, and v2 bytecode
• Freezing an old program fails with invalid-account-data error
• Renouncing rights now requires three transactions: rebuild, upgrade, freeze
• SIMD-0431 requires extending a program by at least 10,240 bytes at a time