I am having trouble finding the published date. I working the Umbraco.Core.Models.IPublishedContent interface, which doesn't seem to have a published date, only a created and updated date.

All the docs I found on the interwebs, suggest using Document(id), then Document.ReleasedDate, but this now marked obsolete. It suggests to use the ReleaseDate in Umbraco.Core.Models.Content class. 

What am I missing?