The pytz library has been replaced with zoneinfo for timezone handling in Contracts.

zoneinfo.ZoneInfo is an allowed native module of the Contracts Language API 4.

All input and output datetime objects within the Contracts (except schedules-related classes, see next bullet point) are now timezone aware and in UTC.

The schedules-related classes (ScheduledEvent, UpdateAccountEventTypeDirective and UpdatePlanEventTypeDirective) datetime objects have to be timezone aware, however, they should be provided in the timezone of the Contract (matching the events_timezone metadata if it is declared, otherwise UTC).

As in 3.x versions, for Contracts with non-UTC events_timezone metadata, schedules’ CRON expression attributes are expected to be in the Contract timezone.