rippled's new MPT subscription stream will label its messages transaction, not mptTransaction

Victoria Shinder12 October 2026, 08:282 min read

The XRP Ledger server rippled merged pull request 8539 on 9 October. It changes one detail of a feature added only a week earlier, and the timing matters: because both changes sit on the development branch, the corrected behaviour is what node operators and client developers should see when the feature reaches a release.

The feature. On 2 October rippled merged PR 5671, which added an mpt_issuances field to the subscribe and unsubscribe RPCs. A client passes a list of MPTIssuanceIDs — identifiers of Multi-Purpose Tokens, the XRPL's newer fungible token type — and the server pushes every validated transaction that affects at least one of those tokens. The aim was to spare clients from subscribing to the full transaction stream and filtering it themselves. As merged, those messages carried a new type, mptTransaction.

The change. PR 8539, by the same author, Shawn Xie, switches the message type back to transaction. The stated reason is consistency: the transactions, transactions_proposed, accounts and books streams all use type: "transaction", and a separate type "has no benefit and creates inconsistency". The PR touches three files, adding 11 lines and removing 16, and its author did not mark it as a public API change — which fits, since the earlier type had not been released.

What developers should do. Anyone who built or tested a client against the development branch during the past week and switched on type === "mptTransaction" should match on transaction instead, and tell MPT updates apart by the subscription they asked for or by the transaction contents. Clients that already route all transaction messages through one handler need no change. Library maintainers adding mpt_issuances support — for example in xrpl.js or xrpl-py — should model the message as an ordinary transaction message.

Context. The same week, rippled published 3.4.1, the security release disclosed by the XRPL Foundation on 9 October; PR 8539 is separate from that and went to the development branch. Neither PR says which release will first include the MPT stream.

Sources: rippled PR 8539 — https://github.com/XRPLF/rippled/pull/8539 ; rippled PR 5671 — https://github.com/XRPLF/rippled/pull/5671