Thunderbird Version: 128.3.3esr (64-bit) Elementary OS 7.1 Email messages received all display in 24 hour format. The calendar is also in 24 hour format. Elementary is configured for AM/PM (per the GUI), and displays as such within the OS. This is a brand new installation of both the OS and Thunderbird. I'm all about RTFM and performing due diligence before asking... but this has me stumped. Largely because I keep running across documentation calling out various strings intl.date* in the Thunderbird configuration. Problem is my instance does not contain a single string containing intl.date. "Date" excludes all searches. Below is one such document referencing these strings. https://enterprise.thunderbird.net/manage-updates-policies-and-customization/thunderbird-preferences-enterprise/customize-thunderbirds-date-and-time-formats Any assistance is appreciated.