Integration features:
- full integration with your phone's calendars and events
- select which phone calendars you want to see on your watch
- define calendar priorities for complications when there's conflict between appointments on different calendars
- next event on Siri watch face

Complications:
- brand new and exclusive DayView graphic rectangular complication: see all your daily appointments together in a timeline on your watch face. Tap it and the app will display your next appointment. Supports up to four simultaneous appointments at a given time. Available for AW4 and later.
- brand new and exclusive DayView circular complication: see all your daily appointments together in a 24-hour clock on your watch face. Recommended for single and sequential appointments. Available for AW4 and later.
- see next event on all complications on Apple Watch Series 0 to 5
- see today's date, event date or 24-hour digital clock on complications

Events list:
- tap the month view to list all your events
- your next event will be displayed by default
- tap an event to see event details

Month scroll:
- scroll through the months with crown or swipe up and down
- force touch on month view to time travel to any month and year, future or past

Customizations:
- all calendar colors (today, next month days, sevent, event today, week day, calendar week, month, year)
- corner, circular and rectangular complications colors
- event list and detail font size
- customize "no more events" message on complications
- customize "no more events" color on corner complication for AW Series 4
- show/hide all day events on complications
- show/hide location on modular watch faces
- choose when week starts: on Sunday or Monday
- show/hide calendar weeks
- turn on/off haptic feedback while scrolling with crown
... and much more

Have fun customizing your calendar to your needs!
And you may discover you don't need stock Calendar app anymore ;-)