(PHP 4 >= 4.2.0, PHP 5, PHP 7) Get internal settings of mbstring

(PHP 5.5.0, PHP 7, PECL >= 3.0.0a1) Convert string from one charset to another

(PHP 5.5.0, PHP 7, PECL >= 3.0.0a1) Get the first day of the week for the calendarʼs locale

(PHP 5 >= 5.2.0, PHP 7) Finds first occurrence of a string within another, case insensitive

(PHP 5 >= 5.3.0, PHP 7, PECL enchant >= 0.1.0 ) Check whether a word is correctly spelled or not

(PHP 7) Check if code point has the Uppercase Unicode property

(PHP 5 >= 5.3.0, PHP 7, PECL intl >= 1.0.0) Quick parse input string

(PHP 7) Check if code point has the Lowercase Unicode property

(PHP 5 >= 5.5.0, PHP 7, PECL intl >= 3.0.0) Sets formatterʼs timezone

(PHP 7) Check if code point is a hexadecimal digit