Branch maybe?

Spin up a Docker container for every timezone, and make sure to destroy the old ones every time the timezone is updated.

Also have at least three instances running, for redundancy and zero-downtime updating.

Which start of time?

  -https://en.wikipedia.org/wiki/Epoch_(reference_date)#Notable_epoch_dates_in_computing
  -https://en.wikipedia.org/wiki/Chronology_of_the_universe#Planck_epoch