Migration to v2 and entry _ids

Currently using v1 as a database from which I’m pulling data into a php based website via the api using the entey _id to identify the data.

I want to start using v2 but I’m not sure about migrating the data.

For example, I have a collection called ‘staff’ with fields ‘first_nane’ and ‘last_name’

John Smith has the _id ‘abc123’

Can I import the data from v1 onto v2 and keep the existing _id values for the imported enties in v2? Or will I have to let the system create the _id?

You can keep the old _id.