Changing field names and types
This article serves to communicate the risks involved in changing a field's name, namespace and/or its data type. It's important to note that ACF won't stop you from carrying out the changes, since the rationale for doing it can vary greatly.
Normally, ACF will show these field properties as read-only for already created fields, but it's possible to edit these fields by clicking the small "lock" icon in the lower left corner of the dialog:
The reason behind making this just a tiny bit difficult is that changing an existing field's definition of name and/or namespace may cause loss of access to any already defined values for that particular scope that use the current name and namespace combination. Or, maybe worse, you may point your new name/namespace combination to some already defined fields (by other apps, maybe) with incompatible values.
Changing a field's data type may cause undesired effects, if the field's existing data is not compatible with the new type and may require changes to your theme.
Please only change a field's type when you know what you are doing and always consult the below table for any issues that may arise. This may not be an exhaustive list of issues that may arise from changing a field's type, so make sure you are planning a change carefully.
A change of a field's type is always possible when there are no existing values tied to the definition (no values entered for a product, a page etc).
However, when existing values are already in place, care must be taken before carrying out a change. Please see the below table for how field types can be changed.
Also note that while something is possible from a technical standpoint, it doesn't mean it's a good idea. But ultimately, this is for you to decide.
Field type change overview
|Current field type||Can be changed to any of||Comments|
|Text||HTML, Markdown, Checkbox, Selection, Tags, Number, Color, (Multi-language Text), (Multi-language HTML)||If changed to a Checkbox, any existing value will cause the checkbox to become checked. To change to a Multi-language field types, get in touch with support beforehand|
|Checkbox||Text, HTML, Selection, Tags||If changed to a Selection, include the value "true" in the list of options|
|Selection||Text, HTML, Markdown, Tags, Number||Only change to a Number if existing selections are single-selection numbers|
|Tags||Text, HTML, Markdown, Selection|
|Number||Text, HTML, Markdown, Selection, Tags|
|Color||Text, HTML, Markdown, Selection, Tags|
| Media v1
||Media v2||Please get in touch with support to ensure a smooth transition|
|Multi-language Text||JSON, Multi-language HTML, Multi-language Markdown|
|Reference to ...||Text, Tags||New Text fields will just reflect any already selected references|