DOM:
    Fixed bug #81433 (DOMElement::setIdAttribute() called twice may remove ID).
FFI:
    Fixed bug #79576 ("TYPE *" shows unhelpful message when type is not defined).
Fileinfo:
    Fixed bug #78987 (High memory usage during encoding detection).
Filter:
    Fixed bug #61700 (FILTER_FLAG_IPV6/FILTER_FLAG_NO_PRIV|RES_RANGE failing).
FPM:
    Fixed bug #81026 (PHP-FPM oob R/W in root process leading to privilege escalation) (CVE-2021-21703).
SPL:
    Fixed bug #80663 (Recursive SplFixedArray::setSize() may cause double-free).
Streams:
    Fixed bug #81475 (stream_isatty emits warning with attached stream wrapper).
XML:
    Fixed bug #70962 (XML_OPTION_SKIP_WHITE strips embedded whitespace).
Zip:
    Fixed bug #81490 (ZipArchive::extractTo() may leak memory).
    Fixed bug #77978 (Dirname ending in colon unzips to wrong dir).