You don’t need to change the ingested type of past data; instead, you can typecast the property to String in your reports so it stops appearing as (not set) for the new text values.
From the docs:
- Mixpanel lets you force a property into another data type via the “Data Type” option in the overflow menu on filters/breakdowns. [Reports overview]
- Properties can be typecast to String, Numeric, Boolean, Date, or List. [Property data types]
What to do:
1. In the report where you’re using this property (e.g. Insights/Funnels), add it as a filter or breakdown.
2. Click the property’s overflow menu (three dots) next to its name.
3. Choose Data Type → String.
This will make Mixpanel treat both the old numeric values and the new prefixed values as strings in that report, so they’ll show up as actual values instead of (not set) / undefined. If you need a reusable field, you can also create a custom property that uses string() to cast the original property to a string. [Custom properties functions]
