Definitely! Here's an article on how to do it:

https://help.klaviyo.com/hc/en-us/articles/1260806293150-How-to-Import-Profile-Properties-Using-a-CSV-Upload

Let me know if that doesn't work

Hi @sbhaiwala,

Thanks for sharing this question with the Klaviyo community and thank you @Mailbox Manny for providing that helpful link!

One note I will add is the steps on exporting your list. This will allow you to start off with a .csv file populated with the contacts that need updating.

To export a list or segment, navigate to your Lists & Segments tab. Click into the list or segment of your choice; for example, a Newsletter list.

Select the Manage List dropdown and choose Export List to CSV.

Make sure when you export, that you select the “Email” field and the custom property field in question. 

Next, update the custom property values in the .csv file for those email addresses. Then follow the steps in the article outlined by Manny to complete the upload of these profiles to a list.

Hope that helps!

Hello I followed the steps provided to update old values for a custom property. When creating a segment and choosing the custom property I still see the values I thought I had overwritten in the dropdown menu. Should this be happening? Thanks.

Hi @vylla001,

Thank you for sharing this question with the community.

Yes, even if you override a custom property value, by default it will still persist in the dropdown menu. If you want to remove these values from the dropdown menu entirely, you can reach out to our support team for assistance. Just let them know the property name and value you wish to remove.

Thanks for being a member of our community.