# pacs.008 Differences from CPMI Harmonisation Requirements

In some cases, Nexus requires additional information, so elements which are defined as **optional** in CPMI or CBPR+ usage guidelines are **mandatory** in Nexus. These are specified in the table below:

<table data-header-hidden data-full-width="true"><thead><tr><th width="172"></th><th width="112"></th><th width="101"></th><th width="118"></th><th></th></tr></thead><tbody><tr><td><strong>ELEMENT</strong></td><td><strong>STATUS IN CPMI</strong></td><td><strong>STATUS IN CBPR+</strong></td><td><strong>STATUS IN NEXUS</strong></td><td><strong>NOTES</strong></td></tr><tr><td>Acceptance Date Time (AccptncDtTm)</td><td>Does not stipulate usage</td><td>Optional</td><td>Mandatory</td><td>Defines the point in time when the payment order from the initiating party meets the processing conditions of the account servicing agent. Required for Timeout and SLA management.</td></tr><tr><td>Clearing System (GrpHdr/SttlmInf/ClrSys)</td><td>Optional</td><td>Optional</td><td>Mandatory</td><td>This is required to identify the domestic instant payment system operator. This is updated by Nexus to reflect the Destination IPS before the payment is sent to the Destination IPS.</td></tr><tr><td>Intermediary Agent 1 and 2 (IntrmyAgt1 and IntrmyAgt2)</td><td>Optional</td><td>Optional</td><td>Recommended</td><td>These are recommended in Nexus to identify the Settlement Account Providers at which the FXP holds funds in both currencies.</td></tr><tr><td>Instruction Identification</td><td>Optional</td><td>Mandatory</td><td>Optional</td><td>UETR is the primary instruction identification used in Nexus. <em>Instruction Identification</em> is therefore optional.</td></tr><tr><td>Instructed Amount (InstdAmt)</td><td>Mandatory</td><td>Optional</td><td>Mandatory</td><td>Mandatory in line with CPMI recommendations.</td></tr><tr><td>Debtor Account (DbtrAcct)</td><td>Recommended</td><td>Optional</td><td>Mandatory</td><td>The Debtor Account is used to identify the account of the Debtor (Sender). This is recommended but not mandatory in CPMI, but mandatory in Nexus.</td></tr><tr><td>Creditor Account (CdtrAcct)</td><td>Recommended</td><td>Optional</td><td>Mandatory</td><td>The Creditor Account is used to identify the account of the Creditor. This is recommended but not mandatory in CPMI, but mandatory in Nexus.</td></tr><tr><td>Agreed Rate (AgrdRate)</td><td>Does not stipulate usage</td><td>Optional</td><td>Mandatory</td><td>Required to convert the amount from Source currency to Destination currency</td></tr><tr><td>Previous Instructing Agent 1 and 2 (PrvsInstgAgt1 and PrvsInstgAgt2)</td><td>Optional</td><td>Optional</td><td>Recommended</td><td>These are recommended in Nexus to identify the Settlement Account Providers at which the FXP holds funds in both currencies.</td></tr></tbody></table>

### Differences against CBPR+

There are also the following notable differences against CBPR+:

* Nexus uses the 2025 version of the ISO 20022 message (`pacs.008.001.13`) while CBPR+ uses an older version (`pacs.008.001.08`)
* Group Header Changes:
  * The Settlement Method of Nexus is defined as CLRG, but this value is removed from CPBR+ as not relevant.
* Transaction Level Changes:
  * Service Level is limited to three repetitions in CBPR+, while this is limited to 1 in Nexus
  * CBPR+ has additional rules on the filling of postal address fields, (in line with CPMI recommendations) to maximise the granularity of postal address details. Nexus strongly recommends this approach but does not yet make it mandatory, meaning that Nexus will not reject a message that uses Address Line fields over dedicated StreetName, TownName, PostalCode elements.