(PHP 7 >= 7.2.0, PHP 8)
mb_chr — Return character by Unicode code point value
$codepoint, ?string $encoding = null): string|falseReturns a string containing the character specified by the Unicode code point value, encoded in the specified encoding.
This function complements mb_ord().
codepoint
      A Unicode codepoint value, e.g. 128024 for U+1F418 ELEPHANT
     
encodingThe encoding
parameter is the character encoding. If it is omitted or null, the internal character
encoding value will be used.
   A string containing the requested character, if it can be represented in the specified
   encoding  or false on failure.
  
| Version | Description | 
|---|---|
| 8.0.0 | encodingis nullable now. | 
Example #1 Testing different code points
<?php
$values = [65, 63, 0x20AC, 128024];
foreach ($values as $value) {
    var_dump(mb_chr($value, 'UTF-8'));
    var_dump(mb_chr($value, 'ISO-8859-1'));
}
?>
The above example will output:
string(1) "A" string(1) "A" string(1) "?" string(1) "?" string(3) "€" bool(false) string(4) "🐘" bool(false)