In these times when everyone is being forced to change how they organise two existing features of radar.squat.net are worth mentioning:
You can cancel events
This makes it clear to visitors that the event was announced, but no longer goes ahead (at that time anyway). On the site this visually
Just go to edit you event. In the field Event status which usually says 'Confirmed' you can change it to 'Cancelled'.
As with updating other events after you hit save you will be asked if you want to update the event. If it's a single one-off event you can just agree. If it's a repeating event you can cancel just that instance, or you can update all future instances, and it will cancel all instances of the event in the future.
You can announce online events
If you are organising an online meeting, where everyone should congregate for the event at the same time, but online.
When adding or changing an event Location there is an Add existing location called Online (and another called Online radio). Online is also a 'country' if you Add a new location and want to do something funky.
Any events with this 'location' will appear in the list of events occurring online.