How is the calendar better in Baya V3/V4?

Refer to the topic linked here.

How to migrate Calendar events from Baya V2 to Baya V3?

Refer to the topic linked here.

My calendar does not show new events

If you have changed your SkyConnect password, then the calendars will not show new events. To see new events, select each calendar, click on the Settings icon in the bottom of the left pane and select Edit. In the dialog box, select the Authentication  tab. Enter the new password and click the Save button.