Payments UK has announced that the ISO 20022 message guidelines have been published after gaining international approval from the ISO 20022 Registration Management Group. The published guidelines are the first in a series. The aim is to develop a catalogue of guidelines covering all the ISO 20022 messages that may be used for real-time payments. These first published guidelines focus on interbank payments messages. The ISO Real-Time Payments Group will now focus on developing the message guidelines necessary for customer-to-bank real-time payments which it hopes to deliver by the end of the summer.