As a side note, I’m going to have to do something similar. I have a client that is requesting that fields that used to have a single value be changed to fields that can have multiple values with added information for each value and I’m going to need to use repeaters for this.
I cannot give specifics, because I have not worked on this yet, but I can tell you what I plan to do.
1) I will create a new repeater field with a new name
2) I will use an acf/prepare_field filter to never show the old field. The field will still exist, but will not be editable by the client. https://www.advancedcustomfields.com/resources/acf-prepare_field/
3) When a post is loaded in the admin to edit I will have an acf/load_value filter for the new repeater field https://www.advancedcustomfields.com/resources/acf-load_value/. This filter will check the old field to see if it has a value and if it does it will transfer this value to the repeater.
4) When the post is saved I will have an acf/save_post action https://www.advancedcustomfields.com/resources/acf-save_post/ that will delete any values in the old field.
5) On the front end I will use the repeater and I will also check the old field for any values and I’ll have different logic and do different things based on where the values are stored.
