Porting Omeka Classic items to Omeka S with added properties

I’m interested in porting an Omeka Classic site to Omeka S. There are over 1000 items on the current site, but I’d like to add a new option to sort by “Date Published” in addition to (or possibly instead of) “Date Created”.

I read that I can create a resource template with new properties, but does that only apply to new items that are created, or will I be able to edit those properties later if I create the template before I import the old site?

Or if there’s another workaround, I’d be interested. Basically, I need to add a “Date Published” property so I can add the date of when the blog post or item was originally published, rather than only being able to sort by the date it was published to the Omeka site.

Omeka S ships with 9 different Date properties in the Dublin Core vocabulary, with Date Issued being the most aligned with your Date Published usage.

Templates don’t allow you to create new custom properties, rather they let you select which ones should be used by default for new items using the template, and allow you to change the displayed name of the property (so, for example, you could use the Date Issued property but use the template to have it displayed as Date Published).

Note also that in S, Date Created is a user-set piece of metadata, like any of the other date fields. Omeka’s internal date is available for sorting but is totally separate from the Date Created property. (In current versions of S, the internal field is just called “Created” to try to maintain a more obvious distinction between the two).