Shared Calendars iOS 9.2.1 Zextras 2.2.2

We are having trouble viewing shared calendars on iOS devices.
Forum research indicates this should be possible on Zextras 2.0+.
Luck (maybe skill) has not been on our side.

The calendar is shared to the user with Admin privileges.
EAS syncs this account to an ipad.
Only the primary calendar is available in the ios Calendar app.

This occurs both ways whether it is a secondary calendar, or a sub-calendar of the primary.

Did we miss a step?

Thanks!