An import will only override the lifecycle stage of existing contacts if the lifecycle stage you select in your import is further down the funnel than the value the contacts have pre-import.During the import process, you'll be required to select a default Lifecycle Stage for your contacts on the Import details screen.
If the lifecycle stage you select on the import is further down the funnel than the lifecycle stage value of your contact pre-import, the selected lifecycle stage on the import will overwrite the pre-import value.
- Example: before the import, the lifecycle stage of your contact is set to Subscriber. You include this contact in your import file, and choose to import that contact list with a Lifecycle Stage of Marketing Qualified Lead. The Lifecycle Stage for your example contact will change from Subscriber to Marketing Qualified Lead because MQL is further down the funnel than Subscriber.
- Example: before the import, the Lifecycle Stage of your contact is set to Sales Qualified Lead. You include this contact in your import file and choose to import that contact list with the Lifecycle Stage of Lead. The Lifecycle Stage for your example contact will not change from Sales Qualified Lead to Lead because Lead is backwards, up the funnel from SQL.
If your import file contains contacts across various lifecycle stages, it is safest to import them with the lifecycle stage of Subscriber (the top of the funnel) and then segment accordingly because the lifecycle stage cannot be moved backwards.
You can find more information about each of the lifecycle stages here.