Protocol 27 Zipper upgrade launches July 8 with authentication delegation for smart accounts (CAP-0071), streamlining multisig implementations and reducing transaction costs. SDKs release June 5-11, testnet upgrade June 18. Developers must review breaking changes and update dependencies before mainnet vote.
Stellar Protocol 27 Zipper introduces authentication delegation for custom smart accounts via CAP-0071-01, enabling wallets and multisig schemes to delegate signing to other addresses without requiring separate authorization entries per signer. Signature payloads now explicitly bind to the top-level account address, preventing cross-account replay attacks. CAP-0071-02 adds address-bound Soroban credentials (V2), closing a narrow replay vulnerability. Release timeline: Stellar Core June 5, RPC and Galexie June 10, SDKs June 5-11, Horizon June 12, testnet upgrade June 18, mainnet protocol vote July 8. Developers should review breaking changes immediately and update SDK dependencies before mainnet vote. Key change: @stellar/stellar-base consolidates into @stellar/stellar-sdk.
