Protocol 30: SDK Changes

XDR Changes

Upgrade to the stellar-xdr v30.0 release (4f524bb), the Protocol 30 XDR. All CAPs are ungated, so no preprocessing feature flags are needed. It covers:

• CAP-84: Muxed Contract Addresses: needs the changes below.
• CAP-88: Millisecond-Resolution Close Times: needs the changes below.
• CAP-87: ML-DSA Signature Verification: regenerate only. It adds ContractCostType values 86–94.

This range also includes stellar-xdr#312: contract spec UDT names go from string<60> to string<1024>, and SCSpecEventV0.name goes from SCSymbol to string<1024>. If a binding generator checks those limits, remove the checks.

CAP-88: Millisecond Close Times

StellarValue.ext gains STELLAR_VALUE_SIGNED_MS = 3 and STELLAR_VALUE_EMPTY_TX_SET_MS = 4, each adding a TimePointMs closeTimeMs field. Every ledger after the upgrade uses one of them, so without the new XDR you cannot decode ledger headers or LedgerCloseMeta (RPC getLedgers, Horizon header_xdr).

Treat the _MS arms like STELLAR_VALUE_SIGNED and STELLAR_VALUE_EMPTY_TX_SET. closeTime is unchanged (whole seconds, closeTimeMs / 1000), and all transaction time bounds stay in seconds, so nothing else changes.

CAP-84: Muxed Contract Addresses

SCAddress gains SC_ADDRESS_TYPE_MUXED_CONTRACT = 5 (MuxedContract { uint64 id; ContractID contractId; }), with a new W... strkey.

• Strkey: version byte 22 << 3 (0xb0); payload is the 32-byte contract ID followed by the 8-byte big-endian ID. Follow SEP-23 and use its W... test vectors.
• Address type: convert arm 5 to and from W... (including equality and SCVal-to-native). Without this, any return value or event holding a muxed contract fails to decode.
• Where W is allowed: only where M is, meaning MuxedAddress params such as the SAC transfer to. Reject W... as a contract to invoke, as an auth signer, in storage keys, and in balance lookups.
• Events: SAC transfer/mint to a W... use the CAP-67 format: the to topic is the base C... and the data is { amount, to_muxed_id }. If you already handle M... destinations, nothing changes.

RPC API Changes

getEvents no longer returns inSuccessfulContractCall (stellar-rpc#1050). The removal ships in the same RPC release but is not part of a Protocol 30 CAP. Make the field optional or remove it from your event model, or parsing will fail.

Horizon API Changes

The contract_credited effect gains optional contract_muxed (the W... address) and contract_muxed_id (a decimal string, like account_muxed_id) fields when a SAC transfer or mint goes to a muxed contract (stellar-horizon#237). Add both as optional fields in your effect model.

Reference Implementations

• js-stellar-sdk (unreleased): XDR in #1795/#1796/#1797; CAP-84 in #1811.
• go-stellar-sdk (v0.8.0): #6015.
• stellar-rpc (unreleased): #1050.
• stellar-horizon (unreleased): #237.