One-Leg Out Instant Credit Transfer Scheme Inter-PSP Implementation Guidelines 2023 version 1.0

These implementation guidelines (IGs) set out the Euro One Leg Out (EOLO) rules for implementing the Inter-Payment Service Provider (Inter-PSP) ISO 20022 XML message standards based on version 1.1 of the 2023 One-Leg Out Instant Credit Transfer (OCT Inst) rulebook, which enters into force on 28 November 2023 at 08:00 CET.

Two distinct sets of OCT Inst Inter-PSP IGs are available: one set for incoming OCT Inst transactions and a second set for outgoing OCT Inst transactions.

EOLO XML Schema Definitions (XSDs) related to the aforementioned IGs are also made available (note: XSD files can be opened via a text editor (e.g. Microsoft Notepad) or XML Schema editor).

EOLO XSDs are not developed for ‘production’ purposes, they are to instantiate the business rules and restrictions contained in the IGs in a formal interchange format, sometimes referred to as Technical Validation Subsets (TVSs). Production instantiations should refer to the default ISO 20022 namespaces.

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