Dates, Files & JSON

• date('Y-m-d H:i') formats the current time: 2026-09-30 14:05. • Common format letters: Y year, m month, d day, D Mon–Sun, M Jan–Dec, H 24-hour, i minutes, s seconds. • DateTimeImmutable is the modern, safer way: $d = new DateTimeImmutable('2026-01-15'); $later = $d->modify('+30 days'); echo $later->format('D, d M Y'); • Differences: $a->diff($b)->days. • Always set the time zone: date_default_timezone_set('America/New_York') or new DateTimeZone(...). Store times in UTC.