UPGRADING

PHP 8.4 UPGRADE NOTES

1. Backward Incompatible Changes
2. New Features
3. Changes in SAPI modules
4. Deprecated Functionality
5. Changed Functions
6. New Functions
7. New Classes and Interfaces
8. Removed Extensions and SAPIs
9. Other Changes to Extensions
10. New Global Constants
11. Changes to INI File Handling
12. Windows Support
13. Other Changes
14. Performance Improvements

========================================
1. Backward Incompatible Changes
========================================

- CLI:
  . The builtin server looks for an index file recursively by traversing parent
    directories in case the specified file cannot be located. This process was
    previously skipped if the path looked like it was referring to a file, i.e.
    if the last path component contained a period. In that case, a 404 error was
    returned. The behavior has been changed to look for an index file in all
    cases.

- Core:
  . The type of PHP_DEBUG and PHP_ZTS constants changed to bool.

- DOM:
  . Added DOMNode::compareDocumentPosition() and DOMNode::DOCUMENT_POSITION_*
    constants.
    If you have a method or constant with the same name, you might encounter errors
    if the declaration is incompatible.
  . Some DOM methods previously returned false or a PHP_ERR DOMException if a new
    node could not be allocated. They consistently throw an INVALID_STATE_ERR
    DOMException now. This situation is extremely unlikely though and probably
    will not affect you. As a result DOMImplementation::createDocument() now has
    a tentative return type of DOMDocument instead of DOMDocument|false.
  . Previously, DOMXPath objects could be cloned, but resulted in an unusable
    object. This is no longer possible, and cloning a DOMXPath object now throws
    an error.

- Intl:
  . resourcebundle_get(), ResourceBundle::get(), and accessing offsets on a
    ResourceBundle object now throw:
    - TypeError for invalid offset types
    - ValueError for an empty string
    - ValueError if the integer index does not fit in a signed 32 bit integer

- MBString:
  . mb_encode_numericentity() and mb_decode_numericentity() now check that
    the $map is only composed of integers, if not a ValueError is thrown.
  . mb_http_input() now always throws a ValueError if the $type is invalid.
  . mb_http_output() now checks that the $encoding parameter does not
    contain any null bytes. If it does, a ValueError is now thrown.
  . On invalid strings (those with encoding errors), mb_substr() now interprets
    character indices in the same manner as most other mbstring functions. This
    means that character indices returned by mb_strpos() can be passed to mb_substr().
  . For SJIS-Mac (MacJapanese) strings, character indices passed to mb_substr() now
    refer to the indices of the Unicode codepoints which are produced when the string
    is converted to Unicode. This is significant because around 40 SJIS-Mac characters
    convert to a sequence of multiple Unicode codepoints.

- ODBC:
  . odbc_fetch_row() returns false when a value less than or equal to 0 is
    passed for parameter $row. Now, a warning is emitted in this case.
  . odbc_connect() and odbc_pconnect() will now return an Odbc\Connection
    object rather than a resource. Return value checks using is_resource()
    should be replaced with checks for `false`.
  . odbc_prepare(), odbc_exec(), and various other functions will now return
    an Odbc\Result object rather than a resource. Return value checks using
    is_resource() should be replaced with checks for `false`.

- Opcache:
  . The JIT config defaults changed from opcache.jit=tracing and
    opcache.jit_buffer_size=0 to opcache.jit=disable and
    opcache.jit_buffer_size=64M, respectively. This does not affect the default
    behavior, the JIT is still disabled by default. However, it is now disabled
    through the opcache.jit setting, rather than opcache.jit_buffer_size. This
    may affect users who previously enabled JIT through opcache.jit_buffer_size
    exclusively, without also specifying a JIT mode using opcache.jit. To enable
    JIT, set the opcache.jit config value accordingly.
  . The maximum value of the opcache.interned_strings_buffer setting on 64bit
    architectures is now 32767 (it was previously 4095).

- PCRE:
  . The bundled pcre2lib has been updated to version 10.43.
    As a consequence, this means {,3} is now recognized as a quantifier instead
    of as text. Furthermore, the meaning of some character classes in UCP mode
    has changed. Consult https://github.com/PCRE2Project/pcre2/blob/master/NEWS
    for a full changelog.

- PDO_DBLIB:
  . setAttribute, DBLIB_ATTR_STRINGIFY_UNIQUEIDENTIFIER and DBLIB_ATTR_DATETIME_CONVERT
    have been changed to set value as a bool.

- PDO_FIREBIRD:
  . getAttribute, ATTR_AUTOCOMMIT has been changed to get the value as a bool.

- PDO_MYSQL:
  . getAttribute, ATTR_AUTOCOMMIT, ATTR_EMULATE_PREPARES, MYSQL_ATTR_DIRECT_QUERY have
    been changed to get values as bool.

- PDO_PGSQL:
  . The DSN's credentials, when set, are given priority over their PDO
    constructor counterparts, being closer to the documentation states.

- PCNTL:
  . The functions pcntl_sigprocmask(), pcntl_sigwaitinfo() and
    pcntl_sigtimedwait() now throw:
    - A ValueError if the $signals array is empty (except for
      pcntl_sigprocmask() if the $mode is SIG_SETMASK).
    - A TypeError if a value of the $signals array is not an integer
    - A ValueError if a value of the $signals array is not a valid signal number
    Moreover, those functions now always return false on failure.
    In some case previously it could return the value -1.
  . The function pcntl_sigprocmask() will also now throw:
    - A ValueError if $mode is not one of SIG_BLOCK, SIG_UNBLOCK, or SIG_SETMASK
  . The function pcntl_sigtimedwait() will also now throw:
    - A ValueError if $seconds is less than 0
    - A ValueError if $nanoseconds is less than 0 or greater than 1e9
    - A ValueError if both $seconds and $nanoseconds are 0

- SimpleXML:
  . Get methods called, or casting to a string on a SimpleXMLElement will no
    longer implicitly reset the iterator data, unless explicitly rewound.
    For example, casting an element to a string within a foreach loop would
    cause an infinite loop because it destroyed the current iterator data.
    This is no longer the case as a consequence of the bugfixes for GH-12192,
    GH-12208, #55098.
  . Calling simplexml_import_dom() with a non-XML object now throws a TypeError
    instead of a ValueError.

- SOAP:
  . SoapClient::$httpurl is now a Soap\Url object rather than a resource.
    Checks using is_resource() (i.e. is_resource($client->httpurl)) should be
    replaced with checks for null (i.e. $client->httpurl !== null).
  . SoapClient::$sdl is now a Soap\Sdl object rather than a resource.
    Checks using is_resource() (i.e. is_resource($client->sdl)) should be
    replaced with checks for null (i.e. $client->sdl !== null).
  . SoapClient::$typemap is now an array rather than a resource.
    Checks using is_resource() (i.e. is_resource($client->typemap)) should be
    replaced with checks for null (i.e. $client->typemap !== null).
  . The SOAP extension gained an optional dependency on the session extension.
    If you build PHP without the session extension and with --enable-rtld-now,
    you will experience errors on startup if you also use the SOAP extension.
    To solve this, either don't use rtld-now or load the session extension.

- SPL:
  . Out of bounds accesses in SplFixedArray now throw an exception of type
    OutOfBoundsException instead of RuntimeException. As OutOfBoundsException
    is a child class of RuntimeException, code that uses RuntimeException
    continues to function.

- Standard:
  . round() now validates the value of the $mode parameter and throws a ValueError
    for invalid modes. Previously invalid modes would have been interpreted as
    PHP_ROUND_HALF_UP.
  . strcspn() with empty $characters now returns the length of the string instead
    of incorrectly stopping at the first NUL character. See GH-12592.

- XML:
  . The xml_set_*_handler() functions now declare and check for an effective
    signature of callable|string|null for the $handler parameters.
    Moreover, values of type string that correspond to method names,
    of object set with xml_set_object() are now checked to see if the method
    exists on the class of the previously passed object.
    This means that xml_set_object() must now always be called prior to setting
    method names as callables.
    Passing an empty string to disable the handler is still allowed,
    but not recommended.

- XSL:
  . XSLTProcessor::setParameter() will now throw a ValueError when its arguments
    contain null bytes. This never actually worked correctly in the first place,
    which is why it throws an exception nowadays.
  . Failure to call a PHP function callback during evaluation now throws
    instead of emitting a warning.
    RFC: https://wiki.php.net/rfc/improve_callbacks_dom_and_xsl
  . Calling XSLTProcessor::importStyleSheet() with a non-XML object now throws
    a TypeError instead of a ValueError.

========================================
2. New Features
========================================

- Core:
  . Added request_parse_body() function that allows parsing RFC1867 (multipart)
    requests in non-POST HTTP requests.
    RFC: https://wiki.php.net/rfc/rfc1867-non-post
  . Getting the debug info for WeakReference will now also output the object
    it references, or null if the reference is no longer valid.
  . The output of Closure::__debugInfo() now includes the name, file, and line
    of the Closure.
  . new expressions with constructor arguments are now dereferencable, meaning
    they allow chaining method calls, property accesses, etc. without enclosing
    the expression in parentheses.
    RFC: https://wiki.php.net/rfc/new_without_parentheses

- Curl:
  . curl_version() returns an additional feature_list value, which is an
    associative array of all known Curl features, and whether they are
    supported (true) or not (false).

- Date:
  . Added static methods
    DateTime[Immutable]::createFromTimestamp(int|float $timestamp): static.
  . Added method DateTime[Immutable]::getMicrosecond(): int.
  . Added method
    DateTime[Immutable]::setMicrosecond(int $microsecond): static.

- DOM:
  . Added constant DOMNode::DOCUMENT_POSITION_DISCONNECTED.
  . Added constant DOMNode::DOCUMENT_POSITION_PRECEDING.
  . Added constant DOMNode::DOCUMENT_POSITION_FOLLOWING.
  . Added constant DOMNode::DOCUMENT_POSITION_CONTAINS.
  . Added constant DOMNode::DOCUMENT_POSITION_CONTAINED_BY.
  . Added constant DOMNode::DOCUMENT_POSITION_IMPLEMENTATION_SPECIFIC.
  . It is now possible to pass any callable to registerPhpFunctions().
    RFC: https://wiki.php.net/rfc/improve_callbacks_dom_and_xsl

- FPM:
  . Flushing headers without a body will now succeed. See GH-12785.

- Intl:
  . NumberFormatter::ROUND_HALFODD added to complement existing
    NumberFormatter::ROUND_HALFEVEN functionality.

- OpenSSL:
  . Added support for Curve25519 + Curve448 based keys. Specifically x25519,
    ed25519, x448 and ed448 fields are supported in openssl_pkey_new and
    openssl_pkey_get_details as well as openssl_sign and openssl_verify were
    extended to support those keys.
    

- Phar:
  . Added support for the unix timestamp extension for zip archives.

- PCRE:
  . The bundled pcre2lib has been updated to version 10.43.
    As a consequence, LoongArch JIT support has been added, spaces
    are now allowed between braces in Perl-compatible items, and
    variable-length lookbehind assertions are now supported.
  . Added support for the "r" (PCRE2_EXTRA_CASELESS_RESTRICT) modifier, as well
    as the (?r) mode modifier. When enabled along with the case-insensitive
    modifier ("i"), the expression locks out mixing of ASCII and non-ASCII
    characters.

- PDO:
  . Added support for driver-specific subclasses.
    RFC: https://wiki.php.net/rfc/pdo_driver_specific_subclasses
    This RFC adds subclasses for PDO in order to better support
    database-specific functionalities. The new classes are
    instantiatable either via calling the PDO::connect() method
    or by invoking their constructor directly.

- PDO_DBLIB:
  . Added class PdoDbLib.

- PDO_FIREBIRD:
  . Added class PdoFirebird.

- PDO_MYSQL:
  . Added class PdoMysql.

- PDO_ODBC:
  . Added class PdoOdbc.

- PDO_PGSQL:
  . Added class PdoPgsql.

- PDO_SQLITE:
  . Added class PdoSqlite.

- POSIX:
  . Added constant POSIX_SC_CHILD_MAX
  . Added constant POSIX_SC_CLK_TCK

- Readfile:
  . Added ability to change .php_history path through PHP_HISTFILE env variable.

- Reflection:
  . ReflectionAttribute now contains a $name property to improve the debugging
    experience.
  . ReflectionClassConstant::__toString() and ReflectionProperty::__toString()
    now returns the attached doc comments.
  . ReflectionConstant was introduced.
  . ReflectionClassConstant::isDeprecated() was introduced.
  . ReflectionGenerator::isClosed() was introduced.

- Standard:
  . stream_bucket_make_writeable() and stream_bucket_new() will now return a
    StreamBucket instance instead of an stdClass instance.
    RFC: https://wiki.php.net/rfc/dedicated_stream_bucket

- SOAP:
  . Added support for clark notation for namespaces in class map.
    It is now possible to specify entries in a class map with clark notation
    to resolve a type with a specific namespace to a specific class.
    For example: '{http://example.com}foo' => 'FooClass'.
  . Instances of DateTimeInterface that are passed to xsd:datetime or similar
    elements are now serialized as such instead of being serialized as an
    empty string.
  . Session persistence now works with a shared session module.

- XSL:
  . It is now possible to use parameters that contain both single and double
    quotes.
  . It is now possible to pass any callable to registerPhpFunctions().
    RFC: https://wiki.php.net/rfc/improve_callbacks_dom_and_xsl
  . Added XSLTProcessor::$maxTemplateDepth and XSLTProcessor::$maxTemplateVars
    to control the recursion depth of XSL template evaluation.

========================================
3. Changes in SAPI modules
========================================

========================================
4. Deprecated Functionality
========================================

- Core:
  . Implicitly nullable parameter types are now deprecated.
    RFC: https://wiki.php.net/rfc/deprecate-implicitly-nullable-types

- Curl:
  . The CURLOPT_BINARYTRANSFER constant is deprecated.

- Date:
  . Calling DatePeriod::__construct(string $isostr, int $options = 0) is
    deprecated. Use DatePeriod::createFromISO8601String() instead.

- Intl:
  . Calling intlcal_set() as well as calling IntlCalendar::set() with
    more than 2 arguments is deprecated. Use either IntlCalendar::setDate()
    or IntlCalendar::setDateTime() instead.
  . Calling intlgregcal_create_instance() as well as calling
    IntlGregorianCalendar::__construct() with more than 2 arguments is
    deprecated. Use either IntlGregorianCalendar::createFromDate() or
    IntlGregorianCalendar::createFromDateTime() instead.

- LDAP:
  . Calling ldap_connect() with more than 2 arguments is deprecated. Use
    ldap_connect_wallet() instead.
  . Calling ldap_exop() with more than 4 arguments is deprecated. Use
    ldap_exop_sync() instead.

- PgSQL:
  . Calling pgsql_fetch_result() with 2 arguments is deprecated. Use the
    3-parameter signature with a null $row parameter instead.
  . Calling pg_field_prtlen() with 2 arguments is deprecated. Use the
    3-parameter signature with a null $row parameter instead.
  . Calling pg_field_is_null() with 2 arguments is deprecated. Use the
    3-parameter signature with a null $row parameter instead.
  . Added pg_result_memory_size to get the visibility the memory used by a query result.

- Reflection:
  . Calling ReflectionMethod::__construct() with 1 argument is deprecated.
    Use ReflectionMethod::createFromMethodName() instead.

- Session:
  . Calling session_set_save_handler() with more than 2 arguments is
    deprecated. Use the 2-parameter signature instead.

- Standard:
  . Calling stream_context_set_option() with 2 arguments is deprecated.
    Use stream_context_set_options() instead.
  . Raising zero to the power of negative number is deprecated.

========================================
5. Changed Functions
========================================

- Core:
  . trigger_error() and user_error() now have a return type of true instead of
    bool.

- DOM:
  . DOMDocument::registerNodeClass() now has a tentative return type of true.
    Previously, the return type was bool but only true could be returned in practice.

- Gettext:
  . bind_textdomain_codeset, textdomain and d(*)gettext functions now throw an exception
    if the domain argument is empty.

- Hash:
  . Changed the return type of hash_update() to true. It was already the case that only
    true could be returned, but the stub was not updated yet.

- Intl:
  . IntlDateFormatter::__construct() throws a ValueError if the locale is invalid.
  . NumberFormatter::__construct() throws a ValueError if the locale is invalid.
  . NumberFormatter::ROUND_TOWARD_ZERO and NumberFormatter::ROUND_AWAY_FROM_ZERO
    have been added as aliases for NumberFormatter::ROUND_DOWN and
    NumberFormatter::ROUND_UP to be consistent with the new PHP_ROUND_* modes.
    RFC: https://wiki.php.net/rfc/new_rounding_modes_to_round_function
  . ResourceBundle::get() now has a tentative return type of:
    ResourceBundle|array|string|int|null

- LibXML:
  . libxml_set_streams_context() now immediately throws a TypeError when a
    non-stream-context resource is passed to the function, instead of throwing
    later when the stream context is used.

- MBString:
  . The behavior of mb_strcut is more consistent now on invalid UTF-8 and UTF-16
    strings. (For valid UTF-8 and UTF-16 strings, there is no change.)

- OpenSSL:
  . The extra_attributes parameter in openssl_csr_new sets CSR attributes
    instead of subject DN which was incorrectly done previously.
  . The dn parameter in openssl_csr_new allows setting array of values for
    a single entry.
  . New serial_hex parameter added to openssl_csr_sign to allow setting serial
    number in the hexadecimal format.

- ODBC:
  . Parameter $row of odbc_fetch_object(), odbc_fetch_array(), and
    odbc_fetch_into() now has a default value of null, consistent with
    odbc_fetch_row(). Previously, the default values were -1, -1, and 0,
    respectively.

- Output:
  . Output handler status flags passed to the flags parameter of ob_start
    are now cleared.

- PDO:
  . getAttribute, enabled to get the value of ATTR_STRINGIFY_FETCHES.

- PDO_FIREBIRD:
  . getAttribute, enabled to get values of FB_ATTR_DATE_FORMAT, FB_ATTR_TIME_FORMAT,
    FB_ATTR_TIMESTAMP_FORMAT.
  . Added new attributes to specify transaction isolation level and access mode.
    Along with these, five constants (PDO::FB_TRANSACTION_ISOLATION_LEVEL,
    PDO::FB_READ_COMMITTED, PDO::FB_REPEATABLE_READ, PDO::FB_SERIALIZABLE,
    PDO::FB_WRITABLE_TRANSACTION) have been added.
  . When using persistent connections, there is now a liveness check in the
    constructor.

- PDO_MYSQL:
  . getAttribute, enabled to get the value of ATTR_FETCH_TABLE_NAMES.

- PDO_PGSQL:
  . getAttribute() can now retrieve the memory usage of query results.
    PDO::PGSQL_ATTR_RESULT_MEMORY_SIZE was added for this feature.

- PGSQL:
  . pg_select, the conditions arguments accepts an empty array and is optional.

- POSIX:
  . posix_isatty now sets the error number when the file descriptor/stream argument
    is invalid.

- Reflection:
  . ReflectionGenerator::getFunction() may now be called after the generator
    finished executing.

- Sockets:
  . Parameter $backlog of socket_create_listen() now has a default value of SOMAXCONN.
    Previously, it was 128.

- SPL:
  . SplPriorityQueue::insert() and SplPriorityQueue::recoverFromCorruption()
    now has a tentative return type of true
  . SplHeap::insert() and SplHeap::recoverFromCorruption()
    now has a tentative return type of true instead of bool

- Standard:
  . The internal implementation for rounding to integers has been rewritten
    to be easier to verify for correctness and to be easier to maintain.
    Some rounding bugs have been fixed as a result of the rewrite. For
    example previously rounding 0.49999999999999994 to the nearest integer
    would have resulted in 1.0 instead of the correct result 0.0. Additional
    inputs might also be affected and result in different outputs compared to
    earlier PHP versions.
  . The default value of the 'cost' option for PASSWORD_BCRYPT for password_hash()
    has been increased from '10' to '12'.

    RFC: https://wiki.php.net/rfc/bcrypt_cost_2023
  . Four new modes have been added to the round() function: PHP_ROUND_CEILING,
    PHP_ROUND_FLOOR, PHP_ROUND_TOWARD_ZERO, PHP_ROUND_AWAY_FROM_ZERO.

    RFC: https://wiki.php.net/rfc/new_rounding_modes_to_round_function
  . debug_zval_dump() now indicates whether an array is packed.
  . Fixed a bug caused by "pre-rounding" of the round() function. Previously, using
    "pre-rounding" to treat a value like 0.285 (actually 0.28499999999999998) as a
    decimal number and round it to 0.29. However, "pre-rounding" incorrectly rounds
    certain numbers, so this fix removes "pre-rounding" and changes the way numbers
    are compared, so that the values are correctly rounded as decimal numbers.
  . long2ip() now returns string instead of string|false.
  . The maximum precision that can be handled by round() has been extended by
    one digit.
  . output_add_rewrite_var() now uses url_rewriter.hosts instead of
    session.trans_sid_hosts for selecting hosts that will be rewritten.

========================================
6. New Functions
========================================

- BCMath:
  . Added bcfloor(), bcceil(), bcround().
    RFC: https://wiki.php.net/rfc/adding_bcround_bcfloor_bcceil_to_bcmath

- DOM:
  . Added DOMNode::compareDocumentPosition().
  . Added DOMXPath::registerPhpFunctionNS().
    RFC: https://wiki.php.net/rfc/improve_callbacks_dom_and_xsl
  . Added DOMXPath::quote() to quote a string for use in an XPath expression.
    Example usage: "//span[contains(text()," . $xpath->quote($string) . ")]"

- Intl:
  . Added IntlDateFormatter::getIanaID()/intltz_get_iana_id() to
    the IANA identifier from a given timezone.
  . Added grapheme_str_split which allow to support emoji and Variation
    Selectors.
  . Added IntlDateFormatter::parseToCalendar which behaves like
    IntlDateFormatter::parse except the time zone is updated.

- MBString:
  . Added mb_trim, mb_ltrim and mb_rtrim functions.
    RFC: https://wiki.php.net/rfc/mb_trim
    Note: this was amended by GH-13820 to fix GH-13815.
  . Added mb_ucfirst and mb_lcfirst functions.
    RFC: https://wiki.php.net/rfc/mb_ucfirst

- Opcache:
  . If JIT is enabled, PHP will now exit with a fatal error on startup in case
    of JIT startup initialization issues.

- PCNTL:
  . Added pcntl_setns allowing a process to be reassociated with a namespace in order
    to share resources with other processes within this context.
  . Added pcntl_getaffinity to get the cpu(s) bound to a process and
    pcntl_setaffinity to bind 1 or more cpus to a process.
  . Added pcntl_getcpu to get the cpu id from where the current process runs.
  . Added pcntl_getqos_class to get the QoS level (aka performance and related
    energy consumption) of the current process and pcntl_setqos_class to set it.

- PDO_PGSQL:
  . Added PDO::pgsqlSetNoticeCallback to allow a callback to be triggered on
    every notice sent (e.g. RAISE NOTICE).

- PGSQL:
  . Added pg_change_password to alter a given user's password. It handles
    transparently the password encryption from the database settings.
  . Added pg_put_copy_data to send COPY commands and pg_put_copy_end to send
    end-of-data to the server.
  . Added pg_socket_poll to check if there is any read and/or write events
    with an optional timeout.

- Sodium:
  . Added the sodium_crypto_aead_aegis128l_*() and sodium_crypto_aead_aegis256l_*()
    functions to support the AEGIS family of authenticated encryption algorithms,
    that was introduced in libsodium 1.0.19.
  . sodium_crypto_aead_aes256gcm_*() functions are now enabled on aarch64 CPUs
    with the ARM cryptographic extensions.

- SPL:
  . Added seek() method to SplObjectStorage, now it implements
    SeekableIterator.

- Standard:
  . Added the http_get_last_response_headers() and
    http_clear_last_response_headers() that allows retrieving the same content
    as the magic $http_response_header variable.
  . Added function fpow() following rules of IEEE 754.
  . Added functions array_find(), array_find_key(), array_all(), and
    array_any().
    RFC: https://wiki.php.net/rfc/array_find

- XSL:
  . Added XSLTProcessor::registerPhpFunctionNS().
    RFC: https://wiki.php.net/rfc/improve_callbacks_dom_and_xsl

========================================
7. New Classes and Interfaces
========================================

- DOM:
  . Implemented DOM HTML5 parsing and serialization.
    RFC: https://wiki.php.net/rfc/domdocument_html5_parser.
    This RFC adds the new Dom namespace along with new classes and
    constant aliases.
    There are two new classes to handle HTML and XML documents:
    Dom\HTMLDocument and Dom\XMLDocument.
    These classes provide a cleaner API to handle HTML and XML documents.
    Furthermore, the Dom\HTMLDocument class implements spec-compliant HTML5
    parsing and serialization.
  . Implemented opt-in ext/dom spec compliance RFC.
    This adds new classes in the DOM namespace that correspond to modern
    equivalents to the old DOM classes in the global namespaces.
    The new classes follow the DOM living spec.
    RFC: https://wiki.php.net/rfc/opt_in_dom_spec_compliance

========================================
8. Removed Extensions and SAPIs
========================================

- IMAP:
  . The IMAP extension has been unbundled and moved to PECL.
    RFC: https://wiki.php.net/rfc/unbundle_imap_pspell_oci8

- PSpell:
  . The pspell extension has been unbundled and moved to PECL.
    RFC: https://wiki.php.net/rfc/unbundle_imap_pspell_oci8

========================================
9. Other Changes to Extensions
========================================

- Curl:
  . The Curl extension now requires at least libcurl 7.61.0.

- Date:
  . The class constants are typed now.

- Intl:
  . The class constants are typed now.
  . The behaviour of Intl class has been normalized to always throw Error
    exceptions when attempting to use a non-initialized object,
    or when cloning fails.
  . The idn_to_ascii() and idn_to_utf8() now always throw ValueErrors if the
    $domain name is empty or too long, and if $variant is not
    INTL_IDNA_VARIANT_UTS46.

- OpenSSL:
  . The OpenSSL extension now requires at least OpenSSL 1.1.1.

- PDO:
  . The class constants are typed now.

- Reflection:
  . The class constants are typed now.

- Spl:
  . The class constants are typed now.

- Sqlite:
  . The class constants are typed now.

- XMLReader:
  . The class constants are typed now.

- XSL:
  . The typed properties XSLTProcessor::$cloneDocument and
    XSLTProcessor::$doXInclude are now declared.

========================================
10. New Global Constants
========================================

- Core:
  . PHP_OUTPUT_HANDLER_PROCESSED.
  . PHP_SBINDIR.

- Intl:
  . The IntlDateFormatter class exposes now the new PATTERN constant
    reflecting udat api's UDAT_PATTERN.
  . The IntlChar class exposes now the new PROPERTY_IDS_UNARY_OPERATOR (new
    IDS binary operator), PROPERTY_ID_COMPAT_MATH_START,
    PROPERTY_ID_COMPAT_MATH_CONTINUE (both for mathematical
    identifier profiling purpose) constants.

- LDAP:
  . LDAP_OPT_X_TLS_PROTOCOL_MAX.
  . LDAP_OPT_X_TLS_PROTOCOL_TLS1_3.

- LibXML:
  . LIBXML_RECOVER.

- OpenSSL:
  . X509_PURPOSE_OCSP_HELPER.
  . X509_PURPOSE_TIMESTAMP_SIGN.

- PCNTL:
  . QosClass::Background (macOs only).
  . QosClass::Default (macOs only).
  . QosClass::UserInteractive (macOs only).
  . QosClass::UserInitiated (macOs only).
  . QosClass::Utility (macOs only).
  . SIGCKPT (DragonFlyBSD only).
  . SIGCKPTEXIT (DragonFlyBSD only).

- Standard:
  . PHP_ROUND_CEILING.
  . PHP_ROUND_FLOOR.
  . PHP_ROUND_TOWARD_ZERO.
  . PHP_ROUND_AWAY_FROM_ZERO.

- Sockets:
  . SO_EXCLUSIVEADDRUSE (Windows only).
  . SOCK_CONN_DGRAM (NetBSD only).
  . SOCK_DCCP (NetBSD only).
  . TCP_SYNCNT (Linux only).
  . SO_EXCLBIND (Solaris/Illumos only).
  . SO_NOSIGPIPE (macOs and FreeBSD).

- Sodium:
  . SODIUM_CRYPTO_AEAD_AEGIS128L_KEYBYTES
  . SODIUM_CRYPTO_AEAD_AEGIS128L_NSECBYTES
  . SODIUM_CRYPTO_AEAD_AEGIS128L_NPUBBYTES
  . SODIUM_CRYPTO_AEAD_AEGIS128L_ABYTES
  . SODIUM_CRYPTO_AEAD_AEGIS256_KEYBYTES
  . SODIUM_CRYPTO_AEAD_AEGIS256_NSECBYTES
  . SODIUM_CRYPTO_AEAD_AEGIS256_NPUBBYTES
  . SODIUM_CRYPTO_AEAD_AEGIS256_ABYTES

- XML:
  . Added XML_OPTION_PARSE_HUGE to allow large inputs in xml_parse and
    xml_parse_into_struct.
    RFC: https://wiki.php.net/rfc/xml_option_parse_huge.

========================================
11. Changes to INI File Handling
========================================

========================================
12. Windows Support
========================================

========================================
13. Other Changes
========================================

* Closure names have been adjusted to include the parent function's name
  and the line of definition to make them easier to distinguish, for example
  within stack traces.

* run-tests.php now skips online tests by default. Set the SKIP_ONLINE_TESTS
  environment variable to 0, or pass the --online flag to run-tests.php to
  execute them.

========================================
14. Performance Improvements
========================================

- BCMath:
  . Improved performance of number conversions and operations.

- Core:
  . Improved the performance of floating point number parsing and formatting in
    ZTS builds under highly concurrent loads. This affects the `printf()` family
    of functions as well as serialization functions such as `json_encode()`,
    `serialize()`.

- DOM:
  . The performance of DOMNode::C14N() is greatly improved for the case without
    an xpath query. This can give a time improvement of easily two order of
    magnitude for documents with tens of thousands of nodes.
  . Improved performance and reduce memory consumption of XML serialization.

- FTP:
  . Improved the performance of FTP uploads up to a factor of 10x for large
    uploads.

- MBString:
  . The performance of strspn() and strcspn() is greatly improved.
    They now run in linear time instead of being bounded by quadratic time.
  . mb_strcut() is much faster now for UTF-8 and UTF-16 strings.
  . Looking up mbstring encoding names is much faster now.
  . The performance of converting SJIS-win to unicode is greatly improved.

- MySQLnd:
  . Improved the performance of MySQLnd quoting.

- PCRE:
  . Improved the performance of named capture groups.

- SimpleXML:
  . Improved performance and reduce memory consumption of XML serialization.

- Standard:
  . Improved the performance of strpbrk().
  . get_browser() is much faster now, up to 1.5x - 2.5x for some test cases.