I wanted a way to set a reminder for the END of an event, but I think that there is no way to do it.

But, I've found an alternative. Doing some search in other calendar applications, I saw one that had "Event end time" as an option for reminders.

So I created a test event and added this reminder to it. Then I went to Google Calendar in web just to check what had it done. And I found out that the other app had added a "time negative" reminder. So, if the event was set to start at 17:00 and end at 18:00, the reminder is shown as "-60 minutes".

The cool thing is that you can't set a negative time for reminders in Google Calendar site (neither in the app), but it's possible to add this kind of reminders by importing an event with an ICS file. Here is an example of this:

BEGIN:VEVENT
DTSTART:20250923T155000Z
DTEND:20250923T160000Z
DTSTAMP:20250923T154651Z
CREATED:20250923T154642Z
LAST-MODIFIED:20250923T154642Z
SEQUENCE:0
STATUS:CONFIRMED
SUMMARY:negative reminder test
TRANSP:OPAQUE
BEGIN:VALARM
ACTION:DISPLAY
TRIGGER:P0DT0H1M0S
DESCRIPTION:This is an event reminder
END:VALARM
END:VEVENT

And finally, the coolest thing is that if you check this event in Google Calendar app, the event reminder is shown with the special text: "x minutes after start", so it really understands that negative time.

So, would it be possible to add to Business Calendar 2 the possibility to add a remainder for some time AFTER the START of the event? (or in other words, allow to set negative time values)