Durable nonces let a pre-signed Solana transaction stay valid indefinitely instead of expiring after about 150 blocks. In April, attackers abused them to drain more than $270M from Drift, and core developers now want the feature removed.

The draft proposal, SIMD-0723, was filed on November 5 by Anza engineer Gabe R. After activation every transaction would need a recent blockhash, and the System Program would stop initializing or advancing nonce accounts. Withdrawals and authority changes on existing accounts keep working.

Mainnet activation is set no earlier than May 5, 2027, giving users at least six months to migrate.

The change mainly hits custodians and exchanges that use air-gapped signing with long approval windows. The proposal points them to onchain signature-verification programs and also cites a 2022 mainnet halt of about 4.5 hours plus several validator bugs tied to nonce handling.