PHP Manual Function Reference Date and Time Related Extensions Date/Time DateTimeImmutable DateTimeImmutable::sub DateTimeImmutable::setTimezone DateTimeInterface DateTimeImmutable::sub (PHP 5 >= 5.5.0)DateTimeImmutable::sub — Subtracts an amount of days, months, years, hours, minutes and seconds Description public DateTimeImmutable DateTimeImmutable::sub ( DateInterval $interval ) Like DateTime::sub() but works with DateTimeImmutable.