Calendars 5 has been updated to version 5.3, adding some features to help manage meatings and events more easily. You can now send and accept event invitations using Calendars 5.
To send an invitation, type in the invitee's name when creating your event. Their contact information should appear below the text field, allowing you to select them and invite them to the meeting. The new notification center in Calendars 5 allows you to manage all of your invitations in one place, allowing you to easily accept or reject them. This update also lets you import .ics files, allowing you to add new events straight from email.
You can download the update now from the App Store.