Solve inconsistencies in e-mail sorting

This guide allows you to better understand the particularities that may arise in the display of e-mails when using different e-mail applications and Infomaniak Mail apps.

Preamble

• It may happen that inconsistencies occur when displaying a list of emails contained within a folder (e.g.: the folder of Messages sent) and that messages sorted and considered to be the latest by one device will not be the same as those displayed when using another tool.

Understanding unique identifiers (UIDs)

UIDs (Unique Identifiers) are unique identifiers assigned to each message in an IMAP mailbox. They are used to uniquely identify each message, regardless of changes made to the folders or messages themselves. UIDs are particularly useful for managing and synchronizing emails on several IMAP software/message clients:

• Each e-mail is assigned a unique UID at the time of its creation in a mailbox; this UID never changes in principle as long as the e-mail exists, even if its content or metadata is changed.
• UIDs are generally sequential, which means that more recent messages have in principle higher UIDs.
• When synchronizing e-mails, IMAP email software/clients can use UIDs to determine which messages are new, modified or deleted since the last synchronization; this allows effective e-mail management without having to download and compare all messages.
• Depending on the tool used, to display them in the order in which they were received, messages can be sorted by their date of receipt or by UID.

Not to be confused with:

• Message Sequence Number (used for temporary operations based on current message position)...
• Message ID (RFC 5322) (used to uniquely identify messages across different servers and software/mail clients)...
• X-Message-Id (specific to the server and used for internal tracking needs)...
• Thread-Index and Thread-Topic (used by Microsoft apps to track conversation threads)...
• GMail Unique Identifiers (used specifically by Gmail to manage messages and threads)...

IMAP applications and Infomaniak Mail app

The problem may appear in this form at the server command level:

758 - date.sent: 2017-10-11 23:15:26 (+0100)
757 - date.sent: 2017-10-11 15:00:55 (+0100)
756 - date.sent: 2017-10-11 14:39:28 (+0100)
(...)
742 - date.sent: 2018-01-17 00:40:21 (+0000)
741 - date.sent: 2018-01-17 00:30:33 (+0000)
740 - date.sent: 2018-01-17 00:26:07 (+0000)
(...)
51 - date.sent: 2022-10-07 16:39:16 (+0100)
50 - date.sent: 2023-06-13 10:15:00 (+0100)
49 - date.sent: 2023-06-07 12:11:35 (+0100)

Here we find that emails dating from 2017 have a UID (758, 757, ...) higher than emails whose date is however more recent in 2023. UIDs had to be reassigned for some reason during the existence of this entire courier account (movements, copies, imports, etc.).

Depending on how the email tool will sort emails, a 2017 message may appear among recent messages while the 2018 message will not be loaded immediately. This is particularly true for Mail Infomaniak which only loads one series of emails at a time based on the UID (this has to evolve).

Therefore, in order to resolve possible inconsistencies, it is recommended to use an IMAP mail client/software as Thunderbird on a computer, which will allow you to quickly and efficiently sort all messages from a specific folder, based on the date of the email, as the application will display all messages on the Infomaniak server.