IMDG Code Amendment 40-20 is mandatory as from 1 June 2022
Amendment 40-20 includes revisions to various Sections of the code and to transport requirements for specific substances. It is mandatory as from 1st June 2022 but may be applied by Administrations in whole or in part on a voluntary basis from 1 Jan 2021.
The amendment Cycle from 2017 - 2026 is as attached:
Source: IMDG Code (imo.org)