User Agent: Mozilla/5.0 (Windows NT 6.3; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/46.0.2490.80 Safari/537.36 Steps to reproduce: Receive Invitation from co-worker. Accept it. Confirmations about changes in events are sent OK. Actual results: No email was send. Expected results: Confirmation should be sent. By comparing logs I noticed that first ocurance lacks of ;SENT-BY="mailto:email@example.com" there is: X-NUM-GUESTS=0:mailto:firstname.lastname@example.org instead of X-NUM-GUESTS=0;SENT-BY="mailto:myemail @mycompany.com":mailto:email@example.com
Are you using caldav or the Google provider addon? In general, the x-props are just roundtripped and not changed by Lightning. Can you please enable calendar.debug.log and calendar.debug.log.verbose and provide what you get in the log when reproducing the issue. To limit the output, you may want to clear the log after TB is up and running but before starting reproducing. You may modify sensitive information, but please make sure to not change data structure.
Created attachment 8679928 [details] Log of first acceptance of invitation Log of first acceptance of invitation
Created attachment 8679930 [details] Log of modification of acceptance of invitation Log of modification of acceptance of invitation - to tentative. This triggered sending confirmation.
Can you also attach the email src you received for the initial invitation? For sensitive information, you can apply he same rule as before. Which email address do you have associated to your calendar - gmail or your corporate address?
I have the same problem using TB 38.3 with Lightning 126.96.36.199 on Linux (Kubuntu 14.04). I have one google calendar synced using the build-in CalDAV functionality. The calendar is associated with my local smtp address (not gmail). If I accept an invitation to this calendar, no message is asking for sending a confirmation e-mail and no e-mail is sent. So the inviting person does not know about my interaction. In some other forum people tell me that this does not work in general with google calendar or CalDAV used. But I do not see any technical reason for this if the calendar is assigned to a local smtp account.
Is this still an issue with TB 45.* / Lightning 4.7.* for you - if so, please provide the information requested in comment 4.
We still need a testcase to proceed