Zipper Goes Live on Stellar Mainnet @StellarOrg has activated the Protocol 27 upgrade, codenamed Zipper, on the Stellar mainnet. The mainnet upgrade vote took place on July 8, 2026, completin
@StellarOrg has activated the Protocol 27 upgrade, codenamed Zipper, on the Stellar mainnet. The mainnet upgrade vote took place on July 8, 2026, completing a rollout that included testnet deployment on June 18 and a series of SDK, RPC, and core releases stretching back to early June.
The upgrade centres on a single but consequential change: making authentication delegation a first-class feature on Stellar, meaning one account can officially authorise another to act on its behalf.Before Zipper, delegation existed on Stellar only as an accidental side effect. Developers who tried to use it faced a tangle of manual steps, extra simulation passes, and bloated transaction sizes, so most teams avoided it entirely.Zipper makes delegation a proper, first-class feature that is dramatically simpler to implement correctly.
Cheaper transactions and more flexible account designs, including social recovery, delegated signing keys, and modular multisig, become practical to build.Transactions also become smaller and cheaper because all delegated signers bundle into a single authorisation entry instead of requiring separate ones.
The upgrade also closes a security gap in the Soroban smart contract environment. 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.
Soroban developers building smart accounts, including wallets, multisig schemes, and account abstraction, will see the most direct benefit.Developers building applications where multiple accounts may share keys, or who want to adopt a more conservative security posture, should plan to migrate to SOROBAN_CREDENTIALS_ADDRESS_V2 after the Protocol 27 upgrade.
Protocol 27 also lays the groundwork for what comes next. The Stellar Development Foundation has confirmed that Protocol 28 will bring contract-based authentication to classic Stellar accounts, and the delegation mechanism in Zipper is a direct prerequisite for that. For $XLM and the broader Stellar ecosystem, Zipper is less a final destination and more the foundation for the next wave of smart account capabilities.
SourcesStellar Development Foundation: Zipper Protocol 27 Upgrade GuideCryptoWisser: Zipper Protocol 27 Is Now Live on Stellar Mainnet
