If you install the traveler 188.8.131.52 you can accept meetings on iPhone
The fix cam be download using this link
New function for Apple Devices (Optional)
The functions listed here were added in Lotus Notes Traveler 184.108.40.206 and are not enabled by default. The Lotus Notes Traveler server administrator must explicitly enable these functions for them to become active. Follow the procedures outlined below to enable.
- Meeting attendee invitation actions for Apple devices.
When this feature is enabled, attendees to meetings will now receive meeting notices on their Apple device and the mobile user will be able to accept, tentatively accept, or decline the meeting invitation. Using the Settings application on the Apple device, the user can enable or disable meeting notice alerts by selecting the Mail, Contacts, Calendars settings and then changing New Invitation Alerts to On or Off.