In PYTHON-767 we added support for a strict_date option. The implementation matches the behavior of MongoDB 2.6 era mongoexport. That is, it outputs ISO-8601 format for post-epoch dates and $numberLong for pre-epoch dates.

With the release of MongoDB 3.0, mongoexport started using ISO-8601 output for pre-epoch dates as well. However, it uses $numberLong for maxDate.

Let's replace the unreleased strict_date boolean with a datetime_representation option, configured with an enum, and use that setting for all datetime output. Something like:

class DatetimeRepresentation:
    # {$date: <int64>}
    LEGACY = 0
    # {$date: {$numberLong: <int64>}}
    NUMBERLONG = 1
    # {$date: <ISO-8601>}
    ISO8601 = 2