a short time ago I performed an upgrade from ZCS 6.0.x to 7.2.1 . After the upgrade, some mailboxes now receive duplicate emails. I searched the forums, and I found that the de-duplication system is configured with zimbraMessageIdDedupeCacheSize attribute: I verified this setting on my server, and it is set to 3000.
What can I check? Or some parameters/settings changed from version 6 to 7?
Thank you in advance.