Lotus iNotes 8.5 supports overlaying Google Calendar feed data within Lotus iNotes calendar views. This article gives step-by-step instructions on how to enable the calendar overlay feature, and how to work with Google calendars. It also discusses limitations in this release. This feature is controlled by a Domino Mail policy setting to enable/disable as shown below. In the Mail policy settings document, the "Allow Calendar Subscription" field should be set to "Enable" to allow this feature to work. You can find out more details about Domino policies in the
Domino Policies or
Domino Policy Precedence Explained articles and about overlaid calendar in the developerWorks article,
New features in IBM Lotus iNotes 8.5: Full mode
.

Adding a Google Calendar
There are 3 ways to add your Google Calendars in Lotus iNotes 8.5:
1-Add a Google Calendar using Google accounts
2-Add a public Google Calendar url to get feed (XML) data. For more details, see
Calendar Addresses for Google calendar
.
3-Add a Google Calendar using Google's private address (aka Magic Cookie URL) to get feed (XML) data. For more details, see
Private Addresses for Google calendar
.
Once it is added, the Google calendar feeds will be overlaid on top of your calendar views and you can check/uncheck the entry easily to display or hide.

Working with a Google Calendar entry
The overlaid Google calendar entries are open in a separate window displaying the Google calendar UI. If the entry is from a private calendar that requires authentication and you have not yet authenticated to the Google site, the Google login page displays and then, once authenticated, you are redirected to the event page.
Limitations
There are some known limitations in this initial release of overlaid Google calendars, especially when compared to similar capability introduced within Lotus Notes 8.5.
- When adding the calendar using Google account, it currently works with your default calendar only, even if you have created multiple calendars in that account.
- The user’s credential information is not persistent. Instead, it is maintained during a session only. You will be prompted to log in to each calendar added using Google accounts per session.
- Other types of overlaid calendars (such as other Notes calendars or iCalendar calendars) are not supported yet.
- The list of configured overlaid calendars and its related settings are not shared with the Lotus Notes 8.5 client.
- This feature is not available when the user is offline or, in a local archive database.