How to get 24 hour time on Raspberry Pi

[jarrod1024]

I am running Thunderbird on a raspberry pi on raspian which i am using as an always on display for the calendar.
I have read online that if your os is set to 24 hour time Thunderbird will also use 24 hour time, however the os is displaying 24 hour time, but Thunderbird is displaying everything in 12 hour time. Does anyone know how to fix this?

Thanks

[jarrod1024]

Found the Solution!
if anyone else wants to do this you have to run "sudo dpkg-reconfigure locales" and change it to en-GB.