PHP 8.1

New Features

HTML entity en/decode functions process single quotes and substitute by default
$GLOBALS variable restrictions
Phar: Default signature algorithm changed from SHA1 to SHA256
SplFixedArray implements JsonSerializable, and json-encodes as an array
CLI: Interactive shell (php -a) requires readline extension
MySQLi: Default error mode set to exceptions
Configurable line endings for fputcsv and SplFileObject::fputcsv
version_compare operator restrictions
Warning on compact function calls with non-string and non-array string parameters
finfo Extension: file_info resource are migrated to existing finfo objects
IMAP: imap resources are IMAP\Connection class objects
FTP Extension: Connection resources are FTP\Connection class objects
GD Extension: Font identifiers are GdFont class objects
LDAP: resources migrated to LDAP\Connection, LDAP\Result, and LDAP\ResultEntry objects
PostgreSQL: resources migrated to PgSql\Connection, PgSql\Result, and PgSql\Lob objects
Pspell: pspell, pspell config resources are PSpell\Dictionary, PSpell\Config class objects

Passing null to non-nullable internal function parameters is deprecated
Return types in PHP built-in class methods and deprecation notices
Serializable interface deprecated
Implicit incompatible float to int conversion is deprecated
mysqli::get_client_info method and mysqli_get_client_info($param) is deprecated
date_sunrise, date_sunset functions and related INI settings are deprecated
strptime function is deprecated
mhash*() functions (hash extension) are deprecated
filter.default and filter.default_options INI settings are deprecated
PDO::FETCH_SERIALIZE is deprecated
auto_detect_line_endings INI directive is deprecated
strftime and gmstrftime functions are deprecated
MySQLi: mysqli_driver->driver_version property is deprecated