Why is "DTSTART;VALUE=DATE" instead of DATE-TIME when IsAllDay = true?

[thehaseebahmed]

This might be my lack of understanding of the iCal format since I'm new to the library and the format in general but why does setting IsAllDay = true on an Event result in the final iCal file having just the date instead of a DateTime? The reason why I ask this is because I'm in a UTC+1 timezone and when storing dates as UTC, the missing Time/TZ info from the final iCal files results in my events being shown 1 day earlier.

I've tried everything possible but the only hack that seems to work is setting "IsAllDay = false" and setting both the start/end dates to be the start/end of the given date. I don't like it and feels like a hack to me so there surely must be a better way.

Thanks!

[axunonb]

The DTSTART property in iCalendar specifies the start date and time for a calendar component, such as an event (VEVENT), a to-do (VTODO), or free/busy time (VFREEBUSY). By default, the value type for DTSTART is DATE-TIME, which includes both the date and the time.

When VALUE=DATE is specified, it means that the DTSTART property only includes the date, without any time component. This is used for all-day events or tasks that span an entire day. For example:

DTSTART;VALUE=DATE:20240101

This indicates that the event starts on January 1, 2024, and lasts the entire day¹(https://icalendar.org/iCalendar-RFC-5545/3-8-2-4-date-time-start.html)²(https://www.kanzaki.com/docs/ical/dtstart.html).

ical.net follows the RFC 5545 specification.