Currencies can be represented in the code in two ways: a three-letter alphabetic code and a three-digit numeric code.
The most recent edition is ISO 4217:2015. The purpose of ISO 4217:2015 is to establish internationally recognised codes for the representation of currencies.
Periodically, amendments must be made to ISO 4217:2015 and these are managed by the Secretariat of the Maintenance Agency, in this case the SIX Interbank Clearing Ltd on behalf of the Swiss Association for Standardization, SNV.
More details on how to contact SIX Interbank Clearing Ltd can be found in the list of Maintenance Agencies.