This tutorial will show you how to connect the iOS Calendar app to your Roundcube calendar. The first step in setting up any third-party app to work with the Roundcube calendar is creating a CalDAV connection. If you haven't done it yet, this tutorial will guide you through the necessary steps.
Please note that this tutorial is a general guide. The CalDAV server on your host may require different settings. If the steps described below don't work for you, please contact your host's or company's tech support and ask them what settings you should use.
1. Add account
Go to Settings / Mail, Contacts, Calendars, click on Other, then click on Add CalDAV Account.
2. Type the calendar details
Type the URL and the user name that you can find in the connection details of your Roundcube calendar. (Make sure to use the URL, not the alternate URL.) Type the password you chose when creating the connection and the description of the calendar. Click Next.
Uncheck the Reminders box and click Save.
When you open the Calendar app and click Calendars you should now see your calendar in the list of calendars.