https://www.avient.com/idea/changing-dynamics-usp
The effective date of the replacement sections was deferred to December 1, 2025 when USP 661 will be replaced by USP 661.1 and USP 661.2.
In the interim, testing under USP 661.1 and USP 661.2 is permitted by USP, and packaging systems conforming to these requirements prior to December 1, 2025 are considered to be in conformance with the USP–NF.