**If a user has multiple external ids in Segment, what happens when they enter an audience or have a computed trait?**

Segment sends an`identify` or a`track` call for each external on the user's account. For example, if a user has three email addresses, and you are sending`identify` calls for your audience, Engage sends three`identify` calls to Mixpanel and adds the latest email address to the user profile as the email “address of record” on the Mixpanel user profile.

**What happens if I receive a`Timestamp must be within the last 5 years` error, and my timestamp displays`1970-01-01`?**

The Segment PHP Library (2.1.0) version requires a UNIX timestamp. If you send anything other than a UNIX timestamp, Segment converts this to the`1970-01-01` timestamp. If you're experiencing failed events due to this error and you have a connected PHP source, update your PHP Library version to 2.1.0.