We've recently upgraded to zimbra 6.0.15 and are setting up free busy with our exchange ews environment. (We've had free busy with webdav working with exchange 2007 public folders for some time.) As things stand now, ZImbra users can see Exchange free busy, but Exchange users cannot see updated Zimbra free busy information. I can look back a few weeks on user calendars and see old free busy information, just not anything since we upgraded zimbra. The public folders are replicating without issue, but the .eml files in the public folders are not getting updated. If I remove the .eml files from the public folders, zimbra does not successfully push new ones into the public folders.

Does anyone have any suggestions how to troubleshoot exactly what kind of http post information zimbra is pushing when it publishes to the public folders? Or does anyone have any other suggestions? I'm at a loss.