PHP 8.3 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
========================================

- Core:
  . Programs that were very close to overflowing the call stack may now throw an
    Error when using more than
    `zend.max_allowed_stack_size-zend.reserved_stack_size` bytes of stack
    (`fiber.stack_size-zend.reserved_stack_size` for fibers).
  . Executing proc_get_status() multiple times will now always return the right
    value on posix systems. Previously, only the first call of the function
    returned the right value. Executing proc_close() after proc_get_status()
    will now also return the right exit code. Previously this would return -1.
    Internally, this works by caching the result on posix systems. If you want
    the old behaviour, you can check the "cached" key in the array returned by
    proc_get_status() to check whether the result was cached.
  . Zend Max Execution Timers is now enabled by default for ZTS builds on
    Linux.
  . Uses of traits with static properties will now redeclare static properties
    inherited from the parent class. This will create a separate static
    property storage for the current class. This is analogous to adding the
    static property to the class directly without traits.
  . Assigning a negative index n to an empty array will now make sure that the
    next index is n+1 instead of 0.
  . Class constant visibility variance is now correctly checked when inherited
    from interfaces.
  . WeakMaps entries whose key maps to itself (possibly transitively) may now
    be removed during cycle collection if the key is not reachable except by
    iterating over the WeakMap (reachability via iteration is considered weak).
    Previously, such entries would never be automatically removed.
  . In addition to whitespace characters, now comments are allowed between
    `yield` and `from`. The whole "construct" (e.g. `yield /* comment */ from`)
    is reported as a single `T_YIELD_FROM` token by the tokenizer.

- DOM:
  . DOMChildNode::after(), DOMChildNode::before(), DOMChildNode::replaceWith()
    on a node that has no parent is now a no-op instead of a hierarchy
    exception, which is the behaviour spec demands.
  . Using the DOMParentNode and DOMChildNode methods without a document now
    works instead of throwing a HIERARCHY_REQUEST_ERR DOMException. This is in
    line with the behaviour spec demands.
  . createAttributeNS() without specifying a prefix would incorrectly create
    a default namespace, placing the element inside the namespace instead of
    the attribute. This bug is now fixed.
  . createAttributeNS() would previously incorrectly throw a NAMESPACE_ERR
    when the prefix was already used for a different uri. It now correctly
    chooses a different prefix when there's a prefix name conflict.
  . New methods and properties were added to some DOM classes. If you inherit
    from these and you happen to have a method or property with the same name,
    you might encounter errors if the declaration is incompatible.
    Consult sections 2. New Features and 6. New Functions for a list of
    newly implemented methods and properties.

- FFI:
  . C functions that have a return type of void now return null instead of
    returning the following object object(FFI\CData:void) { }

- Opcache:
  . The opcache.consistency_checks INI directive was removed. This feature was
    broken with the tracing JIT, as well as with inheritance cache, and has
    been disabled without a way to enable it since PHP 8.1.18 and PHP 8.2.5.
    Both the tracing JIT and inheritance cache may modify shm after the script
    has been persisted by invalidating its checksum. The attempted fix skipped
    over the modifiable pointers but was rejected due to complexity. For this
    reason, it was decided to remove the feature instead.

- Phar:
  . The type of Phar class constants are now declared.

- Standard:
  . The range() function has had various changes:
    * A TypeError is now thrown when passing objects, resources, or arrays
      as the boundary inputs
    * A more descriptive ValueError is thrown when passing 0 for $step
    * A ValueError is now thrown when using a negative $step for increasing ranges
    * If $step is a float that can be interpreted as an int, it is now done so
    * A ValueError is now thrown if any argument is infinity or NAN
    * An E_WARNING is now emitted if $start or $end is the empty string.
      The value continues to be cast to the value 0.
    * An E_WARNING is now emitted if $start or $end has more than one byte,
      only if it is a non-numeric string.
    * An E_WARNING is now emitted if $start or $end is cast to an integer
      because the other boundary input is a number. (e.g. range(5, 'z');)
    * An E_WARNING is now emitted if $step is a float when trying to generate
      a range of characters, except if both boundary inputs are numeric strings
      (e.g. range('5', '9', 0.5); does not produce a warning)
    * range() now produce a list of characters if one of the boundary inputs is
      a string digit instead of casting the other input to int
      (e.g. range('5', 'z');)
  . The file() flags error check now catches all invalid flags. Notably
    FILE_APPEND was previously silently accepted.

- SNMP:
  . The type of SNMP class constants are now declared.

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

- Core
  . Anonymous classes may now be marked as readonly.
  . Readonly properties can now be reinitialized during cloning.
    RFC: https://wiki.php.net/rfc/readonly_amendments
  . Class, interface, trait, and enum constants now support type
    declarations. RFC: https://wiki.php.net/rfc/typed_class_constants
  . Closures created from magic methods can now accept named arguments.
  . The final modifier may now be used when using a method from a trait.
  . Added the #[\Override] attribute to check that a method exists
    in a parent class or implemented interface.
    RFC: https://wiki.php.net/rfc/marking_overriden_methods
  . Class constants can now be accessed dynamically using the C::{$name}
    syntax.
    RFC: https://wiki.php.net/rfc/dynamic_class_constant_fetch
  . Static variable initializers can now contain arbitrary expressions.
    RFC: https://wiki.php.net/rfc/arbitrary_static_variable_initializers

- CLI
  . It is now possible to lint multiple files.

- DOM
  . Added properties DOMElement::className and DOMElement::id.
    These are not binary-safe at the moment because of underlying limitations of
    libxml2. This means that the property values will be cut off at a NUL byte.
  . Added properties DOMNode::isConnected and DOMNameSpaceNode::isConnected.
  . Added properties DOMNode::parentElement and DOMNameSpaceNode::parentElement.

- FFI
  . It is now possible to assign CData to other CData. This means you can
    now assign CData to structs and fields.

- Opcache
  . opcache_get_status()['scripts'][n]['revalidate'] now contains a Unix
    timestamp of when the next revalidation of the scripts timestamp is due,
    dictated by the opcache.revalidate_freq INI directive.

- Posix
  . posix_getrlimit() now takes an optional $res parameter to allow fetching a
    single resource limit.
  . posix_isatty() now raises type warnings for integers following the usual
    ZPP semantics.
  . posix_ttyname() now raises type warnings for integers following the usual
    ZPP semantics and value warnings for invalid file descriptor integers.

- Streams
  . Streams can now emit the STREAM_NOTIFY_COMPLETED notification. This was
    previously not implemented.

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

- $_SERVER['SERVER_SOFTWARE'] value from the built-in CLI server changed to
  make it compliant with RFC3875.

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

- Core
  . Using the ++ operator on empty, non-numeric, or non-alphanumeric strings
    is now deprecated. Moreover, incrementing non-numeric strings is soft
    deprecated and the new str_increment() function should be used instead.
    RFC: https://wiki.php.net/rfc/saner-inc-dec-operators
  . Using the -- operator on empty or non-numeric strings is now deprecated.
    RFC: https://wiki.php.net/rfc/saner-inc-dec-operators
  . Calling get_class() and get_parent_class() without arguments is now
    deprecated.

- DBA
  . Calling dba_fetch() with $dba as the 3rd argument is now deprecated.

- FFI
  . Calling FFI::cast(), FFI::new(), and FFI::type() statically is now
    deprecated.

- Intl
  . The U_MULTIPLE_DECIMAL_SEP*E*RATORS constant had been deprecated, using
    the U_MULTIPLE_DECIMAL_SEP*A*RATORS instead is recommended.
  . The NumberFormatter::TYPE_CURRENCY has been deprecated.

- LDAP
  . Calling ldap_connect() with separate hostname and port is deprecated.
    RFC: https://wiki.php.net/rfc/deprecations_php_8_3#deprecate_calling_ldap_connect_with_2_parameters

- MBString
  . Passing a negative $width to mb_strimwidth() is now deprecated.

- Phar
  . Calling Phar::setStub() with a resource and a length is now deprecated.
    Such calls should be replaced by:
    $phar->setStub(stream_get_contents($resource));

- Random
  . The MT_RAND_PHP Mt19937 variant is deprecated.
    RFC: https://wiki.php.net/rfc/deprecations_php_8_3#mt_rand_php

- Standard:
  . The assert_options() function is now deprecated.
  . The ASSERT_ACTIVE, ASSERT_BAIL, ASSERT_CALLBACK, ASSERT_EXCEPTION, and
    ASSERT_WARNING constants have been deprecated.
    RFC: https://wiki.php.net/rfc/assert-string-eval-cleanup

- SQLite3
  . Using exceptions is now preferred, warnings will be removed in the future.
    Calling SQLite3::enableExceptions(false) will trigger a depreciation
    warning in this version.

- Zip:
  . The ZipArchive::FL_RECOMPRESS constant is deprecated and will be removed
    in a future version of libzip

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

- Core:
  . gc_status() has added the following 8 fields:
    "running" => bool
    "protected" => bool
    "full" => bool
    "buffer_size" => int
    "application_time" => float: Total application time, in seconds (including
    collector_time)
    "collector_time" => float: Time spent collecting cycles, in seconds
    (including destructor_time and free_time)
    "destructor_time" => float: Time spent executing destructors during
    cycle collection, in seconds
    "free_time" => float: Time spent freeing values during cycle collection, in
    seconds
    See GH-9336, GH-11523
  . class_alias() now supports creating an alias of an internal class.
  . Setting `open_basedir` at runtime using `ini_set('open_basedir', ...);` no
    longer accepts paths containing the parent directory (`..`). Previously,
    only paths starting with `..` were disallowed. This could easily be
    circumvented by prepending `./` to the path.
  . User exception handlers now catch exceptions during shutdown.
  . The resultant HTML of highlight_string and highlight_file has changed.
    Whitespace between outer HTML tags is removed. Newlines and spaces
    are no longer converted to HTML entities. The whole HTML is now wrapped in
    <pre> tag. The outer <span> has been merged with <code>.

- Calendar
  . easter_date() now supports years from 1970 to 2,000,000,000 on 64-bit
    systems, previously it only supported years in the range from 1970 to 2037.

- Curl:
  . curl_getinfo() now supports two new constants: CURLINFO_CAPATH and
    CURLINFO_CAINFO. If option is null, the following two additional keys are
    present: "capath" and "cainfo".

- Dom:
  . Changed DOMCharacterData::appendData() tentative return type to true.
  . DOMDocument::loadHTML(), DOMDocument::loadHTMLFile(),
    DOMDocument::loadXML() and DOMDocument::loadXMLFile() now have a tentative
    return type of bool. Previously, this was documented as having a return
    type of DOMDocument|bool, but DOMDocument cannot be returned since PHP 8.0
    as it is no longer statically callable.

- Gd:
  . Changed imagerotate signature, removed the `ignore_transparent` argument
    as it was not used internally anyway from PHP 7.x.

- Intl:
  . datefmt_set_timezone (and its alias IntlDateformatter::setTimeZone)
    now returns true on success, previously null was returned.
  . IntlBreakiterator::setText() now returns false on failure, previously
    null was returned.
    now returns true on success, previously null was returned.
  . IntlChar::enumCharNames is now returning a boolean.
    Previously it returned null on success and false on failure.
  . IntlDateFormatter::construct throws an U_ILLEGAL_ARGUMENT_ERROR
    exception when an invalid locale had been set.

- MBString:
  . mb_strtolower, mb_strtotitle, and mb_convert_case implement conditional
    casing rules for the Greek letter sigma. For mb_convert_case, conditional
    casing only applies to MB_CASE_LOWER and MB_CASE_TITLE modes, not to
    MB_CASE_LOWER_SIMPLE and MB_CASE_TITLE_SIMPLE.
  . mb_decode_mimeheader interprets underscores in QPrint-encoded MIME
    encoded words as required by RFC 2047; they are converted to spaces.
    Underscores must be encoded as "=5F" in such MIME encoded words.
  . In rare cases, mb_encode_mimeheader will transfer-encode its input
    string where it would pass it through as raw ASCII in PHP 8.2.
  . mb_encode_mimeheader no longer drops NUL (zero) bytes when
    QPrint-encoding the input string. This previously caused strings in
    certain text encodings, especially UTF-16 and UTF-32, to be
    corrupted by mb_encode_mimeheader.
  . mb_detect_encoding's "non-strict" mode now behaves as described in the
    documentation. Previously, it would return false if the same byte
    (for example, the first byte) of the input string was invalid in all
    candidate encodings. More generally, it would eliminate candidate
    encodings from consideration when an invalid byte was seen, and if the
    same input byte eliminated all remaining encodings still under
    consideration, it would return false. On the other hand, if all candidate
    encodings but one were eliminated from consideration, it would return the
    last remaining one without regard for how many encoding errors might be
    encountered later in the string. This is different from the behavior
    described in the documentation, which says: "If strict is set to false,
    the closest matching encoding will be returned."

- mysqli:
  . mysqli_fetch_object now raises a ValueError instead of an Exception when
    the constructor_args argument is non empty with the class not having
    constructor.
  . mysqli_poll now raises a ValueError when the read nor error arguments are
    passed.
  . mysqli_field_seek and mysqli_result::field_seek now specify return type
    as true instead of bool.

- ODBC
  . odbc_autocommit() now accepts null for the $enable parameter.
    Passing null has the same behaviour as passing only 1 parameter,
    namely indicating if the autocommit feature is enabled or not.

- PGSQL:
  . pg_fetch_object now raises a ValueError instead of an Exception when the
    constructor_args argument is non empty with the class not having
    constructor.
  . pg_insert now raises a ValueError instead of a WARNING when the table
    specified is invalid.
  . pg_insert and pg_convert raises a ValueError or a TypeError instead of a
    WARNING when the value/type of a field does not match properly with a
    PostGreSQL's type.
  . The $row param of pg_fetch_result(), pg_field_prtlen() and
    pg_field_is_null() is now nullable.

- Random:
  . Changed mt_srand() and srand() to not check the number of arguments to
    determine whether a random seed should be used. Passing null will generate
    a random seed, 0 will use zero as the seed. The functions are now
    consistent with Mt19937::__construct().

- Reflection:
  . Return type of ReflectionClass::getStaticProperties() is no longer nullable.
  . Calling ReflectionProperty::setValue() with only one parameter is deprecated.
    To set static properties, pass null as the first parameter.

- Standard:
  . E_NOTICEs emitted by unserialize() have been promoted to E_WARNING.
    RFC: https://wiki.php.net/rfc/improve_unserialize_error_handling
  . unserialize() now emits a new E_WARNING if the input contains unconsumed
    bytes.
    RFC: https://wiki.php.net/rfc/unserialize_warn_on_trailing_data
  . array_pad() is now only limited by the maximum number of elements an array
    can have. Before, it was only possible to add at most 1048576 elements at a
    time.
  . strtok() raises a warning in the case token is not provided when starting
    tokenization.
  . password_hash() will now chain the underlying Random\RandomException
    as the ValueError’s $previous Exception when salt generation fails.
  . proc_open() $command array must now have at least one non empty element.
  . proc_open() returns false if $command array is invalid command instead of
    resource object that produces warning later. This was already the case for
    Windows but it is now also the case if posix_spawn implementation is in use
    (most Linux, BSD and MacOS platforms). There are still some old platforms
    where this behavior is not changed as posix_spawn is not supported there.
  . array_sum() and array_product() now warn when values in the array cannot
    be converted to int/float. Previously arrays and objects where ignored
    whilst every other value was cast to int. Moreover, objects that define
    a numeric cast (e.g. GMP) are now casted instead of ignored.
    RFC: https://wiki.php.net/rfc/saner-array-sum-product
  . number_format() $decimal parameter handles rounding to negative places. It
    means that when $decimals is negative, $num is rounded to $decimals
    significant digits before the decimal point. Previously negative $decimals
    got silently ignored and the number got rounded to zero decimal places.
  . The $before_needle argument added to strrchr() which works in the same way
    like its counterpart in strstr() or stristr().
  . str_getcsv() and fgetcsv() return empty string instead of a string with
    a single zero byte for the last field which contains only unterminated
    enclosure.

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

- Date:
  . Added DatePeriod::createFromISO8601String() as a replacement for the
    overloaded constructor of DatePeriod.

- DOM:
  . Added DOMNode::contains().
  . Added DOMElement::getAttributeNames().
  . Added DOMNode::getRootNode(). The $options argument does nothing at the
    moment because it only influences the shadow DOM, which we do not support
    yet.
  . Added DOMParentNode::replaceChildren().
  . Added DOMNode::isEqualNode().
  . Added DOMElement::insertAdjacentElement() and
    DOMElement::insertAdjacentText().
  . Added DOMElement::toggleAttribute().

- Intl:
  . Added IntlCalendar::setDate() and IntlCalendar::setDateTime()
    as partial replacements for the overloaded IntlCalendar::set() method.
  . Added IntlGregorianCalendar::createFromDate() and
    IntlGregorianCalendar::createFromDateTime()
    as partial replacements for the overloaded IntlGregorianCalendar
    constructor.

- JSON:
  . Added json_validate(), which returns whether the json is valid for
    the given $depth and $options.
    RFC: https://wiki.php.net/rfc/json_validate

- LDAP:
  . Added ldap_connect_wallet().
  . Added ldap_exop_sync().

- MBString:
  . Added mb_str_pad(), which is the mbstring equivalent of str_pad().
    RFC: https://wiki.php.net/rfc/mb_str_pad

- Posix:
  . Added posix_sysconf call to get runtime informations.
  . Added posix_pathconf call to get configuration value from a directory/file.
  . Added posix_fpathconf call to get configuration value from a file
    descriptor.
  . Added posix_eaccess call to check the effective user id's permission for
    a path.

- PGSQL:
  . Added pg_set_error_context_visibility to set the visibility of the context
    in error messages (with libpq >= 9.6).

- Random:
  . Added Randomizer::getBytesFromString().
    RFC: https://wiki.php.net/rfc/randomizer_additions
  . Added Randomizer::nextFloat(), ::getFloat(), and IntervalBoundary.
    RFC: https://wiki.php.net/rfc/randomizer_additions

- Reflection:
  . Added ReflectionMethod::createFromMethodName().

- Sockets:
  . Added socket_atmark to checks if the socket is OOB marked.

- Standard:
  . Added the str_increment() and str_decrement() functions.
    RFC: https://wiki.php.net/rfc/saner-inc-dec-operators
  . Added stream_context_set_options() as a replacement for
    stream_context_set_option() when passed an array of options.

- Zip:
  . Added ZipArchive::setArchiveFlag and ZipArchive::getArchiveFlag methods.

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

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

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

- Core:
  . WeakMaps now have ephemeron-like behavior: Entries whose key maps to itself
    (possibly transitively) may be removed during cycle collection if the key
    is not reachable except by iterating over the WeakMap (reachability via
    iteration is considered weak). Previously, such entries would never be
    automatically removed. (See GH-10932.)
  . The ++ and -- operators now emit warnings when attempting to increment
    values of type bool as this will change in the next major version.
    A warning is emitted when trying to decrement values of type null, as
    this will change in the next major version.
    Internal objects that implement an _IS_NUMBER cast but not a do_operator
    handler that overrides addition and subtraction now can be incremented
    and decrement as if one would do $o += 1 or $o -= 1

- DOM:
  . The DOM lifetime mechanism has been reworked such that implicitly removed
    nodes can still be fetched. Previously this resulted in an exception.

- SQLite3
  . The SQLite3 class now throws \SQLite3Exception (extends \Exception) instead
    of \Exception.
  . The SQLite error code is now passed in the exception error code instead of
    being included in the error message.

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

- Curl:
  . CURLINFO_CAPATH
  . CURLINFO_CAINFO
  . CURLOPT_MIME_OPTIONS
  . CURLMIMEOPT_FORMESCAPE
  . CURLOPT_WS_OPTIONS
  . CURLWS_RAW_MODE
  . CURLOPT_SSH_HOSTKEYFUNCTION
  . CURLOPT_PROTOCOLS_STR
  . CURLOPT_REDIR_PROTOCOLS_STR
  . CURLOPT_CA_CACHE_TIMEOUT
  . CURLOPT_QUICK_EXIT
  . CURLKHMATCH_OK
  . CURLKHMATCH_MISMATCH
  . CURLKHMATCH_MISSING
  . CURLKHMATCH_LAST

- Intl:
  . MIXED_NUMBERS (Spoofchecker).
  . HIDDEN_OVERLAY (Spoofchecker).

- OpenSSL:
  . OPENSSL_CMS_OLDMIMETYPE
  . PKCS7_NOOLDMIMETYPE

- PCNTL:
  . SIGINFO

- PDO_ODBC
  . PDO_ODBC_TYPE

- PGSQL:
  . PGSQL_TRACE_SUPPRESS_TIMESTAMPS
  . PGSQL_TRACE_REGRESS_MODE
  . PGSQL_ERRORS_SQLSTATE
  . PGSQL_SHOW_CONTEXT_NEVER
  . PGSQL_SHOW_CONTEXT_ERRORS
  . PGSQL_SHOW_CONTEXT_ALWAYS

- Posix:
  . POSIX_SC_ARG_MAX
  . POSIX_SC_PAGESIZE
  . POSIX_SC_NPROCESSORS_CONF
  . POSIX_SC_NPROCESSORS_ONLN
  . POSIX_PC_LINK_MAX
  . POSIX_PC_MAX_CANON
  . POSIX_PC_MAX_INPUT
  . POSIX_PC_NAME_MAX
  . POSIX_PC_PATH_MAX
  . POSIX_PC_PIPE_BUF
  . POSIX_PC_CHOWN_RESTRICTED
  . POSIX_PC_NO_TRUNC
  . POSIX_PC_ALLOC_SIZE_MIN
  . POSIX_PC_SYMLINK_MAX

- Sockets:
  . SO_ATTACH_REUSEPORT_CBPF (Linux only).
  . SO_DETACH_BPF (Linux only).
  . SO_DETACH_FILTER (Linux only).
  . TCP_QUICKACK (Linux only).
  . IP_DONTFRAG (FreeBSD only).
  . IP_MTU_DISCOVER (Linux only).
  . IP_PMTUDISC_DO (Linux only).
  . IP_PMTUDISC_DONT (Linux only).
  . IP_PMTUDISC_WANT (Linux only).
  . IP_PMTUDISC_PROBE (Linux only).
  . IP_PMTUDISC_INTERFACE (Linux only).
  . IP_PMTUDISC_OMIT (Linux only).
  . AF_DIVERT (FreeBSD only).
  . SOL_UDPLITE.
  . UDPLITE_RECV_CSCOV.
  . UDPLITE_SEND_CSCOV.
  . SO_RERROR (NetBSD only).
  . SO_ZEROIZE (OpenBSD only).
  . SO_SPLICE (OpenBSD only).
  . TCP_REPAIR (Linux only).
  . SO_REUSEPORT_LB (FreeBSD only).
  . IP_BIND_ADDRESS_NO_PORT (Linux only).

- Zip:
  . ZipArchive::ER_DATA_LENGTH (libzip >= 1.10)
  . ZipArchive::ER_NOT_ALLOWED (libzip >= 1.10)
  . ZipArchive::AFL_RDONLY (libzip >= 1.10)
  . ZipArchive::AFL_IS_TORRENTZIP (libzip >= 1.10)
  . ZipArchive::AFL_WANT_TORRENTZIP (libzip >= 1.10)
  . ZipArchive::AFL_CREATE_OR_KEEP_FILE_FOR_EMPTY_ARCHIVE (libzip >= 1.10)
  . ZipArchive::FL_OPEN_FILE_NOW
  . ZipArchive::LENGTH_TO_END as default value for addFile and replaceFile
  . ZipArchive::LENGTH_UNCHECKED (libzip >= 1.10.1)

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

- assert.*
  . The assert.* INI settings have been deprecated.
    This comprises the following INI settings:
     - assert.active
     - assert.bail
     - assert.callback
     - assert.exception
     - assert.warning
    If the value of the setting is equal to the default value, no deprecation
    notice is emitted.
    The zend.assertions INI setting should be used instead.

- zend.max_allowed_stack_size
  . New INI directive to set the maximum allowed stack size. Possible
    values are `0` (detect the process or thread maximum stack size), `-1`
    (no limit), or a positive number of bytes. The default is `0`. When it
    is not possible to detect the the process or thread maximum stack size,
    a known system default is used. Setting this value too high has the same
    effect as disabling the stack size limit. Fibers use fiber.stack_size
    as maximum allowed stack size. An Error is thrown when the process call
    stack exceeds `zend.max_allowed_stack_size-zend.reserved_stack_size`
    bytes, to prevent stack-overflow-induced segmentation faults, with
    the goal of making debugging easier. The stack size increases during
    uncontrolled recursions involving internal functions or the magic methods
    __toString, __clone, __sleep, __destruct.  This is not related to stack
    buffer overflows, and is not a security feature.

- zend.reserved_stack_size
  . New INI directive to set the reserved stack size, in bytes. This is
    subtracted from the max allowed stack size, as a buffer, when checking the
    stack size.

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

- Minimum supported Windows version has been bumped to Windows 8 or
  Windows Server 2012

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

- Core:
  . An Error is now thrown when the process call stack exceeds a certain size,
    to prevent stack-overflow-induced segmentation faults, with the goal of
    making debugging easier. The maximum allowed stack size is controlled
    by the INI directives zend.max_allowed_stack_size,
    zend.reserved_stack_size and fiber.stack_size.

- FFI:
  . FFI::load() is now allowed during preloading when opcache.preload_user is
    the current system user. Previously, calling FFI::load() was not possible
    during preloading if the opcache.preload_user directive was set.

- FPM:
  . FPM CLI test now fails if the socket path is longer than supported by OS.

- Opcache:
  . In the cli and phpdbg SAPIs, preloading does not require the
    opcache.preload_user directive to be set anymore when running as root. In
    other SAPIs, this directive is required when running as root because
    preloading is done before the SAPI switches to an unprivileged user.

- Streams:
  . Blocking fread() on socket connection returns immediately if there are
    any buffered data instead of waiting for more data.
  . Memory stream no longer fails if seek offset is past the end. Instead
    the memory is increase on the next write and date between the old end and
    offset is filled with zero bytes in the same way how it works for files.
  . stat() access operations like file_exists() and similar will now use real
    path instead of the actual stream path. This is consistent with stream
    opening.

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

- DOM:
  . Looping over a DOMNodeList now uses caching. Therefore requesting items no
    longer takes quadratic time by default.
  . Getting text content from nodes now avoids an allocation, resulting in a
    performance gain.
  . DOMChildNode::remove() now runs in O(1) performance.

- Standard:
  . The file() flags error check is now about 7% faster.

- SPL:
  . RecursiveDirectoryIterator now performs less I/O when looping over a
    directory.