I'm running SmarterMail Enterprise on Ubuntu Server 24.04.1 and I upgraded SmarterMail from Build 9056 to 9084. In Build 9084, the From field at the top of new emails ("new" meaning emails that Outlook retrieved for the first time from the SmarterMail server while Build 9084 was installed, regardless of the SmarterMail server build that was running at the time the email was received from the sender by the SmarterMail server) shown in Outlook via MAPI is malformed and appears as follows:

From: Nick Jansen <nick@example.com>; <From: "Nick Jansen" <nick@example.com>;>

Or if the sender didn't have a display name, it looks malformed like this (it shouldn't have From: or the semicolon):

From: nick@example.com;

In Build 9056, it shows correctly as follows:

Nick Jansen <nick@example.com>

Or, for a sender without a display name:

nick@example.com

The From field in Webmail, Thunderbird via IMAP, and the Android Gmail app via EAS, appears correctly. I downgraded back to Build 9056 and the From field appears correctly again in Outlook via MAPI for new emails that Outlook retrieved after the downgrade.

Emails retrieved during 9084 remained wrong after downgrading to Build 9056, but for folders with affected items (just the inbox for me), with SmarterMail Build 9056 running, right clicking the email folder in Outlook, clicking Properties, clicking Clear Offline Items, and letting Outlook redownload all the messages in the folder caused the From fields from the previously-wrong messages to appear correctly again.

I'm using Office 2019 Outlook Version 2410 (Build 18129.20158 Click-to-Run), 64-bit, on Windows 11 Pro 24H2.