- mb_convert_encoding: documentation ( source)
- base64_decode: documentation ( source)
- str_replace: documentation ( source)
<?php
$string = 'zeAg6+7q4Ov87e7sIPHl8OLl8OUg7/DoIOL75+7i5SD08+3q9ujoIHN0cl9yZXBsYWNlIO/w7uHr5ewg7eUg4u7n7ejq4OXy';
$string = base64_decode($string);
echo $string, PHP_EOL;
$needle = 'сервере';
$replace = '=======';
$string = mb_convert_encoding($string, 'utf8', 'cp1251');
echo $string, PHP_EOL;
echo str_replace($needle, $replace, $string);