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 1.0 of the 2025 One-Leg Out Instant Credit Transfer (OCT Inst) rulebook, which enters into force on 5 October 2025 at 03:30 CET.
This exceptional October entry-into-force date – deviating from the usual end of November publication - has been chosen in light of the entry into force dates of Regulation (EU) 2024/886, regarding instant credit transfers in euro, also known as the Instant Payments Regulation (“IPR”), amending Regulation (EU) 260/2012, also known as the SEPA Regulation. The same entry-into-force date has been selected for all relevant EPC schemes in order to facilitate the implementation preparation for PSPs, Clearing and Settlement Mechanisms (CSMs) and other technical service providers.
Two distinct sets of OCT Inst Inter-PSP IGs are available: one for incoming OCT Inst transactions and the other for outgoing OCT Inst transactions.
The main changes compared to the previous versions are outlined in section 3 of version 1.0 of the 2025 OCT Inst Inter-PSP IGs.
In addition, EOLO XML Schema Definitions (XSDs) related to IGs are made available. These XSD files can be accessed using a text editor (e.g. Microsoft Notepad) or an XML Schema editor.
Disclaimer:
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.