3v4l.org

run code in 300+ PHP versions simultaneously
<?php var_dump( $conv = mb_convert_encoding( $bin = hex2bin("fe7ff9cb"), "UTF-8", "CP936" ), mb_check_encoding($bin, "CP936"), bin2hex(mb_convert_encoding($conv, "CP936", "UTF-8")) );
Output for 8.1.0 - 8.1.15, 8.2.0 - 8.2.2
string(4) "?" bool(false) string(6) "3ff9cb"
Output for 7.4.0 - 7.4.33, 8.0.1 - 8.0.27
string(4) "" bool(false) string(6) "7ff9cb"

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