@Gabriele- I was able to install a trial version of Kerio Mailserver so I could check out the Operations logging you noted. Here are some example logs I was able to get generated in testing:
[25/Oct/2021 16:38:38] {DELETE} Protocol: HTTP/WebMail, User: admin@test.local, IP: 127.0.0.1, Folder: ~admin@test.local/Sent Items, From: "Administrator" <admin@test.local>, Subject: "Test", Delivered: 25/Oct/2021 16:38:31, Size: 466
[25/Oct/2021 16:38:42] {DELETE} Protocol: HTTP/WebMail, User: admin@test.local, IP: 127.0.0.1, Folder: ~admin@test.local/INBOX, From: "Administrator" <admin@test.local>, Subject: "Test", Delivered: 25/Oct/2021 16:38:31, Size: 466
[25/Oct/2021 16:38:46] {DELETE} Protocol: HTTP/WebMail, User: admin@test.local, IP: 127.0.0.1, Folder: ~admin@test.local/Sent Items, From: "Administrator" <admin@test.local>, Subject: "Test", Delivered: 25/Oct/2021 16:38:31, Size: 466
As you can see the logging is pretty limited, and seems to register all of my moves and deletes as delete operations! I compared this to SmarterMail and found the following logging for similar operations in the Administrative logs:
[2021.10.25] 16:42:38.289 [xxx.xxx.xxx.xxx] Webmail Login successful: With user admin-logging@example.com
[2021.10.25] 16:42:44.836 [xxx.xxx.xxx.xxx] User admin-logging@example.com calling set mail settings
[2021.10.25] 16:42:56.884 [xxx.xxx.xxx.xxx] User admin-logging@example.com calling send message, subject: Test
[2021.10.25] 16:43:00.571 [xxx.xxx.xxx.xxx] User admin-logging@example.com calling move messages, owner: admin-logging@example.com, folder: sent items, newOwner: admin-logging@example.com, new folder: inbox, count: 1
[2021.10.25] 16:43:03.868 [xxx.xxx.xxx.xxx] User admin-logging@example.com calling move messages, owner: admin-logging@example.com, folder: inbox, newOwner: admin-logging@example.com, new folder: sent items, count: 1
[2021.10.25] 16:43:05.775 [xxx.xxx.xxx.xxx] User admin-logging@example.com calling delete messages, folder: sent items, owner: admin-logging@example.com, all: , count: 1
[2021.10.25] 16:43:06.040 [xxx.xxx.xxx.xxx] User admin-logging@example.com calling patch message, owner: admin-logging@example.com, count: 1, folder: sent items
So, I think the general administrative logging is a little more detailed in our case, and I recommend checking out those logs for an Operations log alternative in SmarterMail. Let me know what you think :-)