What is the difference between WIPO Standard ST.25 and ST.26 for Sequence Listings?

This page is an FAQ based on guidance from the Manual of Patent Examining Procedure. It is provided as guidance, with links to the ground truth sources. This is information only: it is not legal advice.

WIPO Standard ST.25 and ST.26 are two different formats for submitting Sequence Listings in patent applications. The key differences are:

• ST.25 is the older format, used for applications filed before July 1, 2022.
• ST.26 is the new XML-based format, required for applications filed on or after July 1, 2022.

The MPEP explains the transition:

“Though 37 CFR 1.821 through 1.825 remain applicable for applications with a filing date before July 1, 2022, those provisions will not be applicable to applications filed on or after July 1, 2022.”

This means that applicants must use the new ST.26 XML format for all new applications filed on or after July 1, 2022, even if they are claiming priority to applications that used the older ST.25 format.