In the old version one of the main gripes was that fact you only got alerted of events on the day they happen. So say for example the calendar alerted you of a birthday, you'd have no time to send a card or buy a present. In the new version however you can set the calendar to remind you of events up to 5 days in advance...


OLD NEW

 

But, if you like to only know of events the day they happen, then you can set the new alert system to do that too...

 

The 'Don't Remind me again today' option is for people who need to restart their computers several times a day. In the old version, you would be notifed of events every time windows started, which some users found frustrating.