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Stellar’s pending Bell upgrade, also called Protocol 30, is scheduled for a mainnet upgrade vote on November 23, 2026 at 1700 UTC, with a testnet vote earlier on November 3 at the same time, according to Ambcrypto. The Stellar Development Foundation announced the release on October 20, and Stellar Core v30.0.0 became available on October 16, Blockonomi reported.
Ambcrypto described Bell as an initial step into post-quantum security, aimed at making smart accounts ready for businesses at scale and beginning work on two longer-term goals: quantum-safe signatures and faster ledgers.
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Key facts
- Testnet and mainnet upgrade votes are set for November 3 and November 23, 2026, both at 1700 UTC, per Blockonomi and U.today.
- CAP-84 adds muxed contract addresses: a contract address can carry a 64-bit ID written in a format starting with W.
- CAP-87 lets smart contracts verify ML-DSA signatures, the post-quantum standard NIST finalized in 2024, with Stellar Core performing the verification directly.
- CAP-88 moves ledger close times to a millisecond clock; Protocol 28 had already cut mainnet close times from about 5.7 seconds to 5 seconds in September.
- Ambcrypto reported XLM bounced about 5% after the update and was up 7% on the week, while U.today put it at $0.183, up 4.80% over 24 hours at the time of writing.
Muxed addresses and millisecond timing
Exchanges, ramps and custodial products on Stellar already use muxed accounts, which attach an ID to a single account so each customer gets a unique deposit address while funds land in one place. Smart accounts had no equivalent, forcing businesses holding customer balances to run one contract per customer. CAP-84 closes that gap.
Jake Urban, Senior Engineering Manager at the Stellar Development Foundation, described the W as an upside-down M, according to Blockonomi. He said the distinct type lets developers always know which address they are handling. Developers must update SDKs and add the W variant to type checks.
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The ledger header format also changes under CAP-88, so tools reading ledger data need updated XDR definitions, and Blockonomi advised SDK users to upgrade before the votes. U.today noted that an older SDK may fail to decode Protocol 30 ledgers, while the Protocol 30 SDKs carry updated XDR definitions plus support for the new address type. The previous closeTime field still reports whole seconds.
Quantum plans and the 2029 benchmark
Stellar secures accounts with Ed25519, secp256k1 and secp256r1 elliptic-curve signatures. A large enough quantum computer could break these in theory; no such machine is publicly known, but public keys remain visible on the ledger and migrations take years. Verification of ML-DSA needs far more computation than Ed25519, which is why Stellar Core handles it rather than contract code, keeping calls cheap and allowing testing against official vectors.
Network transaction signatures remain Ed25519 for now. A native post-quantum signer for classic accounts is planned for a later protocol change, and Stellar has targeted full quantum-safety across its stack by 2027. Ambcrypto framed the work against Google’s 2029 internal deadline for making its own systems quantum-secure, which it urged the blockchain industry to adopt. Stellar introduced its Quantum Preparedness Plan in June 2026, according to U.today, and Bell is the first onchain piece of it.
Why it matters
The upgrade puts Stellar alongside Tron and Starknet in the post-quantum race. For businesses, muxed contract addresses remove the need to deploy a contract per customer, and quantum-safe signing becomes available at the contract level before it reaches standard wallets. Because account addresses on the network encode Ed25519 public keys directly, every address, including dormant ones, is a potential target, which explains the staged approach. U.today reported XLM was set to benefit in the long run from the security improvements.
What to watch
The November 3 testnet vote at 1700 UTC is the first checkpoint; a successful result leads to the mainnet vote on November 23. On the market side, Ambcrypto noted that only a decisive move above $0.19 could confirm an extension of the recovery, with bulls defending the September low and support at $0.17. This is not financial advice, and crypto markets are volatile and uncertain.
Reported by ambcrypto.com.
Sources: AMBCrypto, Blockonomi, U.today