DateTimeImmutable::modify Creates a new object with modified timestamp &reftitle.description; public DateTimeImmutableDateTimeImmutable::modify stringmodify Creates a new DateTimeImmutable object with modified timestamp. The original object is not modified. &reftitle.parameters; &date.datetime.description.modified; modify &date.formats.parameter; &reftitle.returnvalues; Returns the newly created object&return.falseforfailure;.