Date Text Format available in ISO 8601 format (e.g. 2025-03-14)

[spozzi99]

I'm a fan of the ISO date format, it makes much more sense, is region independent and also good to sort with. Thunderbird just supports the short and long fixed (for central European slightly weird) format. Any chance to add ISO 8601 format to the Settings > Calendar > Date Text Format ?!?

[Jon]

Thanks for submitting an idea to the Mozilla Connect community! Your idea is now open to votes (aka kudos) and comments.

[pg_78]

Go to the "Config Editor" (it's at the bottom of Settings > General, it's Thunderbird's equivalent of Firefox's about:config). Create a string preference:

intl.date_time.pattern_override.date_short

and give it a value of:

YYYY-MM-dd

This means that Thunderbird will use ISO8601 as the short date format in most places. It will show up as an option in the Settings > Calendar > Date Text Format.

For reference in the Thunderbird docs, see: https://enterprise.thunderbird.net/manage-updates-policies-and-customization/thunderbird-preferences...

[spozzi99]

Thank you, @pg_78 , exactly what I was looking for 🙂

[pg_78]

@spozzi99 Great! I find this gives me my preferred date formats almost everywhere. The only gap I've found is in some calendar views - for example, the "Week" and "Multiweek" views seem to be hardcoded to formats like "Tue Apr 1".