No. You can prepare a spreadsheet containing just the information you want to add or update, together with a way to identify each subscriber. You do not need to include every field shown in a subscriber profile.

For example, to update first names using email addresses, your file might contain only:

Other details, such as addresses or custom fields, can be left out. Your organisation's import rules may require additional fields; include those as well.

Map at least one available identifier: Email, Phone or External ID. Subscriber ID is available only when enabled. Additional required fields must be mapped and populated on every row you import.

On Map columns, give every included column one of these decisions:

• Accept a field: import its values into the selected Taguchi field.
• Ignore column: leave reference information out of the import.

Check the effect on existing information:

• Omitted or ignored fields remain unchanged.
• Blank cells in mapped columns follow each field's import rules and can clear some values.

See blank-cell behaviour.

Create any missing subscriber custom-field definitions in Settings before uploading. The mapping screen lets you select existing fields; it does not create missing fields for you.

See uploading subscriber data into a list.