phacility/phabricator · warning · Exception

Timezone "%s" is not a valid timezone identifier.

Error message

Timezone "%s" is not a valid timezone identifier.

What it means

The timezone setting validates the submitted value against DateTimeZone::listIdentifiers() (the IANA tz database bundled with PHP), cached in a static per request. Any value not in that list - abbreviations like EST/PDT, offsets like UTC+2, misspellings, Windows zone names, or identifiers from a different tzdata version than the server's - throws this exception.

Source

Thrown at src/applications/settings/setting/PhabricatorTimezoneSetting.php:47

    // NOTE: This isn't doing anything fancy, it's just a much faster
    // validator than doing all the timezone calculations to build the full
    // list of options.

    if (!$value) {
      return;
    }

    static $identifiers;
    if ($identifiers === null) {
      $identifiers = DateTimeZone::listIdentifiers();
      $identifiers = array_fuse($identifiers);
    }

    if (isset($identifiers[$value])) {
      return;
    }

    throw new Exception(
      pht(
        'Timezone "%s" is not a valid timezone identifier.',
        $value));
  }

  protected function getSelectOptionGroups() {
    $timezones = DateTimeZone::listIdentifiers();
    $now = new DateTime('@'.PhabricatorTime::getNow());

    $groups = array();
    foreach ($timezones as $timezone) {
      $zone = new DateTimeZone($timezone);
      $offset = ($zone->getOffset($now) / 60);
      $groups[$offset][] = $timezone;
    }

    ksort($groups);

View on GitHub (pinned to 5720a38cfe)

Solutions

1. Use exact IANA identifiers: 'America/Los_Angeles', 'Europe/Berlin', 'UTC'
2. Source the value from the settings dropdown - it is generated from the same listIdentifiers() call
3. Update PHP's timezonedb (e.g. PECL timezonedb) if a genuinely valid new zone is rejected
4. Never send abbreviations, offsets, or Windows timezone display names

Example fix

// before
"PST8PDT"
// or "UTC-8"

// after
"America/Los_Angeles"

$valid = array_fuse(DateTimeZone::listIdentifiers());
if (!isset($valid[$value])) {
  // reject before posting: use an exact IANA identifier
}

function isValidTimezoneIdentifier($tz) {
  return is_string($tz) && in_array($tz, DateTimeZone::listIdentifiers(), true);
}

When it happens

Trigger: Posting settings/timezone with 'EST', 'PDT', 'GMT+2', 'Pacific Standard Time' (Windows name), 'America/Los_Angeles' (typo), or a recently added IANA zone unknown to the server's older timezonedb.

Common situations: API/Conduit clients sending offsets or abbreviations; free-text inputs instead of the dropdown; PHP built with an outdated timezonedb extension rejecting newer zone names.

Related errors

• Service "%s" is unrecognized, restricted, or you do not have
• When creating a new Almanac interface via the Conduit API, y
• Device "%s" is unrecognized, restricted, or you do not have
• Interfaces must have a unique combination of network, device
• Another namespace with this name already exists. Each namesp

AI-assisted analysis of phacility/phabricator@5720a38cfe (2026-08-21). Data as JSON: /api/errors/e77ec2f08c14af5f. Report an issue: GitHub.