iconv_mime_decode() unavailable on some old PHP versions

[piRGoif]

Hello, I wanted to check iconv_mime_decode PHP function results on various PHP versions including old ones (7.4.33 especially). With a snippet like this one :

$value = 'my string to decode';
echo iconv_mime_decode($value, ICONV_MIME_DECODE_CONTINUE_ON_ERROR, 'UTF-8');

But with multiple PHP versions I get the error : "Call to undefined function iconv_mime_decode()" :

• 7.4.33 (but ok in 7.4.32)
• 5.4.0 - 5.4.45
  (and multiple PHP 4 versions)