Questions Regarding Customer.io Data Retention and Event Migration

I have a few questions:

1. As we know, Customer.io only stores our events for 30 days, and data beyond that period is no longer accessible. Could you confirm if there's an option to extend the retention period?

2. We have created two campaigns for email migration from Mailter to automate emails on customers who last visited beyond 3 days. We capture the timestamp using the built-in event_timestamp field in Customer.io. Do you see any concerns with this approach?

3. How can we backfill the event timestamp for our new or old events through Customer.io? Since we are working on migrating more emails to Customer.io, we’re wondering if there's a better way to handle this.

Looking forward to your insights.

Best,
Zoey