A series can run for weeks or months, but a calendar only needs the hours each session is live. Now one ICS file can hold multiple events: one for each session the registrant signed up for, with its own date, time and link.
With Make each session its own calendar event turned on, the ICS file attached to your series' confirmation email holds multiple events: one for each upcoming session the registrant is registered for, soonest first.
Each event carries its own session's title, date, time and link, plus the reminder you set, so every session shows up on the day it happens and the weeks between sessions stay free.

| Switch off | Switch on | |
|---|---|---|
| Events in the ICS file | One, for the series | One for each session |
| Time it holds on the calendar | From the series' start to its end | Each session's own hours |
| Title and link | The series' | Each session's own |
Open your series, then Emails → Registration.



BigMarker builds the one file for each registrant from the sessions they're registered for.
| The registrant | Their calendar file |
|---|---|
| Registered for the series | One file with an event for every upcoming session (sessions copy the series' registrations by default) |
| Chose their sessions in an itinerary series | One file with an event for each session they chose |
| Has no upcoming sessions left | One event for the series |
Past and canceled sessions are left out, and a file holds up to 50 events.
On the Settings tab, two settings hold still while each session is its own event, and come back to your choices when you turn it off.
| Setting | While it's on |
|---|---|
| Auto-add to calendar | Held at Off: the calendar arrives as a file registrants open, because a calendar with several events can't carry an invite |
| Replace Calendar Event | Locked: each session's event uses that session's own identifier |

The option lives on a series' Registration Confirmation Email. Calendar files on the series' other emails keep one event, and a file you upload with Upload Custom ICS is sent as you made it.