Core:
    Fixed bug #72595 (php_output_handler_append illegal write access).
    Fixed bug #66719 (Weird behaviour when using get_called_class() with call_user_func()).
    Fixed bug #81305 (Built-in Webserver Drops Requests With "Upgrade" Header).
BCMath:
    Fixed bug #78238 (BCMath returns "-0").
CGI:
    Fixed bug #80849 (HTTP Status header truncation).
GD:
    Fixed bug #51498 (imagefilledellipse does not work for large circles).
MySQLi:
    Fixed bug #74544 (Integer overflow in mysqli_real_escape_string()).
OpenSSL:
    Fixed bug #81327 (Error build openssl extension on php 7.4.22).
PDO_ODBC:
    Fixed bug #81252 (PDO_ODBC doesn't account for SQL_NO_TOTAL).
Phar:
    Fixed bug #81211: Symlinks are followed when creating PHAR archive.(cmb)
Shmop:
    Fixed bug #81283 (shmop can't read beyond 2147483647 bytes).
Standard:
    Fixed bug #72146 (Integer overflow on substr_replace).
    Fixed bug #81265 (getimagesize returns 0 for 256px ICO images).
    Fixed bug #74960 (Heap buffer overflow via str_repeat).
Streams:
    Fixed bug #81294 (Segfault when removing a filter).