Migrating from pytz to ZoneInfo (python 3.9+)

December 9, 2023

Django 5.0 removed pytz in favor of python 3.9+ supported ZoneInfo.

Adding tzinfo to naked datetime using pytz:

    pytz.timezone("Europe/Helsinki").localize(non_tz_datetime)

becomes

    non_tz_datetime.replace(tzinfo=ZoneInfo("Europe/Helsinki"))

Converting to timezone using pytz:

    timestamp.astimezone(pytz.timezone("Europe/Helsinki"))

becomes

    timestamp.astimezone(ZoneInfo("Europe/Helsinki"))

Note that ZoneInfo is not available before python 3.9 so to support 3.8 (we have couple of old servers) need to import ZoneInfo with

    try:
        import zoneinfo  # noqa
    except ImportError:
        from backports import zoneinfo  # type: ignore  # noqa
    from zoneinfo import ZoneInfo

and in requirements.txt install it with

    backports.zoneinfo;python_version<"3.9"

;python_version<“3.9” skips installing backports.zoneinfo that line with when python >= 3.9