# Encoding or timezone shift: pre-release checklist

Source: https://releasefailures.com/incidents/encoding-or-timezone-shift/
Content version: 1.0.0
Verified on: 2026-10-22
Licence: CC BY 4.0

Definition: Stored timestamps or strings are shifted or corrupted after a driver, locale or timezone change.
- [ ] PR-01 Assert in every environment that the application timezone configuration variable is set to a non-NULL value before the serving change goes live. (test class: Configuration and environment tests)
- [ ] PR-02 Diff the timezone and locale settings of the new serving layer against the old one and block the release on any difference. (test class: Configuration and environment tests)
- [ ] PR-03 Run a timezone-based calculation through each warehouse driver connection type with an account set to a non-default timezone and compare the result to a stored expected value. (test class: Integration tests)
- [ ] PR-04 Write a timestamped record through the dashboard in a lower environment and confirm the stored value matches the wall clock time in the account timezone. (test class: Integration tests)
- [ ] PR-05 Add a post-change smoke step that creates a note, reads its timestamp back and fails if the offset differs from the account timezone. (test class: Synthetic monitoring)
- [ ] PR-06 Run one synthetic check as an account with a custom timezone, filter a query by date and confirm the returned rows match a stored expected set. (test class: Synthetic monitoring)