Adding a new attribute and populating it via list upload

I have added a new (hidden) attribute to an existing subscriber database. I now want to populate that attribute/field with data that I have in a delimited text file, without changing all other data associated with the other attributes for each subscriber in the database. I want to add this data retrospectively to existing subscribers using a file that I have created on my local machine, without changing any of the other existing data for each subscriber. I also only want to populate this attribute for a subset of my whole subscriber list, and some of the subscribers will be on multiple lists - I add this only for information, not because I believe this will cause an issue.

I have searched but am not confident I have found the right way of doing this. Any help gratefully received.

@XrtX You should be able to use a file containing only the email address and the single attribute.

Thank you. If I do that, will not the entries being uploaded overwrite the existing entry for the same e-mail address already on phplist, and if I elect not to overwrite it, won’t it create a duplicate? I’m basing these scenarios on the options I see available when I go to import subscribers.


There is nothing to overwrite.