Aller au contenu principal
Was this helpful?

i18n Migration Plan

Scope​

Enable multilingual behavior for existing single-language deployments with safe rollback.

Rollout Steps​

  1. Deploy backend code with nestjs-i18n and new locale files.
  2. Run DB migration:
    • users.preferred_language
    • organisations.default_language
  3. Backfill preferred_language from existing users.language.
  4. Deploy frontend with language switcher and i18n runtime.
  5. Enable feature flag (if used) for multilingual UI.
  6. Validate production with smoke tests:
    • login
    • profile language update
    • notification/email language resolution

Backward Compatibility​

  • Existing users.language remains populated and is mirrored from preferred_language.
  • Missing translation keys fall back to English.

Rollback​

  1. Disable frontend language switcher feature flag.
  2. Redeploy previous frontend bundle.
  3. Redeploy previous backend image.
  4. Keep DB columns in place (non-breaking), or run down migration if required.

Verification Checklist​

  • PATCH /api/users/me/language returns updated language.
  • <html lang> updates after switch.
  • API error/success messages remain valid.
  • Email channel still sends notifications with fallback templates.