Octal Integer
Integers can be specified in octal, or base 8, notation. Octal integer syntax starts with 0o, zero-o, and only contains digits from 0 to 7.
Initially, octal integers were formatted by simply starting with a initial 0. This features is still available, yet should be replaced with the less confusing syntax with 0o.
<?php
// 12
$octal = 0O14;
$octal = 014;
?>