No need for an event necessarily.
Just this last Spring they released
- New iMacs
- New iPad Mini
- New AirPods (v2) with Wireless Charging Case
- New Accesorries
- New iPad Air
All released done with just press releases and no special event.
The event was the following week and not about those products -- in fact they released them in advance to clear the decks *for* that event and not distract it's focus.
Apple stock got a boost from a series of new releases this week before Monday's Apple event, including new iPads, Macs and AirPods.
investorplace.com