> The encoding parameter was moved from the third position to the fourth in PHP 5.2.0.
> For backward compatibility, encoding could be specified as the third parameter, but doing
> so is deprecated and will be removed in the future.

Between PHP 5.2 and PHP 7.3, this was a deprecation in documentation only.
As of PHP 7.4, a deprecation warning will be thrown if an encoding is passed as the 3rd argument.
As of PHP 8, the argument is expected to change to accept an integer only.

Refs:
* https://wiki.php.net/rfc/deprecations_php_7_4#mb_strrpos_with_encoding_as_3rd_argument
 * php/php-src@39e756e

jrfnl mentioned this pull request

wimg approved these changes Aug 28, 2019