If i create an event from Google and accept from mail module, the accept response status work properly. But when i modify this event in Google calendar and accept it from eGroupware mail, the response status notification is missed.
The notification settings in calendar are set properly (notify external addresses).
I mean, this concerns appointments that you have created as an organiser. It should therefore be irrelevant in your described case.
You mean a confirmation of your decision => Google calendar of the organiser?
So when you change an external appointment that already exists in your calendar?
Yes, the confirmation of my decision with a previously accepted, but modified event → Google organizer.
The first invitation works as expected.
Only accept an event in eGroupware that was accepted before, but its have a new event update (like time change on Google side). No modification on local side.
I think the second answer contains the organizer as an attendee also (with chair, but with needs-action), wich is confusing the system.
Also, there are multiple UID is in the answers. I think this UID needs to identify the event.