Current version is based on a [draft of 4.0.0](https://legacy.iho.int/iho_pubs/draft_pubs/S-52_e6.1.0/S-52_e6.1.0_and_PresLib_e4.0.0.htm) that is available online. I am in the process of purchasing the latest v4.0.4 from IHO.
Current version is based on a draft of 4.0.0 that is available online.
I am in the process of purchasing the latest v4.0.4 from IHO.