# Custom Interchange Version Control Number Code

> You can now set a custom Interchange Version Control Number Code (ISA-12) for generated EDI files.

Published Feb 8, 2024

Product: EDI platform

You can now set a custom Interchange Version Control Number Code ([`ISA-12`](https://www.stedi.com/edi/x12/segment/ISA#ISA-12)) for generated EDI files.

When you call the Generate EDI API, the outbound transaction setting ID you provide dictates which Stedi Guide will be used for validation and translation. By default, Stedi sets `ISA-12` to be the X12 release number of the associated guide. However, some trading partners may require that you specify a different release for the transaction and the `ISA` envelope – for example, you might send a transaction from X12 release `003020` inside an ISA envelope with an Interchange Version Control Number Code of `00401`.

Visit the Generate EDI docs for complete details about `ISA` and `GS` overrides.