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.
Fiber switching during destructor execution is now allowed. It was previously blocked due to conflicts with garbage collection.
Destructors may now be executed in a separate Fiber:
When garbage collection is triggered in a Fiber, destructors called by the GC are executed in a separate Fiber: the gc_destructor_fiber. If this Fiber suspends, a new one is created to execute the remaining destructors. The previous gc_destructor_fiber is not referenced anymore by the GC and may be collected if it's not referenced anywhere else. Objects whose destructor is suspended will not be collected until the destructor returns or the Fiber is collected.
    Output handler status flags passed to the flags
    parameter of ob_start() are now cleared.
   
    output_add_rewrite_var() now uses
    url_rewriter.hosts
    instead of
    session.trans_sid_hosts
    for selecting hosts that will be rewritten.
   
Support for EOL Apache 2.0 and 2.2 has been removed. Minimum required Apache version is now 2.4.
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.
Flushing headers without a body will now succeed.
Status page has a new field to display a memory peak.
    
    The /dev/poll events.mechanism
    setting for Solaris/Illumos had been retired.
   
trigger_error() and user_error() now have a return type of true instead of bool.
    DOMDocument::registerNodeClass()
    now has a tentative return type of true instead of
    bool.
    It could only ever return true in practice.
   
    hash_update()
    now has a tentative return type of true instead of
    bool.
    It could only ever return true in practice.
   
    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.
   
    ResourceBundle::get()
    
    now has a tentative return type of ResourceBundle|array|string|int|null.
   
    The idn_to_ascii() and idn_to_utf8()
    functions now always throw ValueErrors
    if the domain name is empty or too long.
   
    The idn_to_ascii() and idn_to_utf8()
    functions now always throw ValueError
    if the variant parameter is not
    INTL_IDNA_VARIANT_UTS46.
   
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.
The behavior of mb_strcut() is more consistent now on invalid UTF-8 and UTF-16 strings. There is no behavioural change for valid UTF-8 and UTF-16 strings.
    The row of
    odbc_fetch_object(),
    odbc_fetch_array(), and
    odbc_fetch_into() now have a default value of null,
    consistent with odbc_fetch_row().
    Previously, the default values were
    -1,
    -1,
    and 0,
    respectively.
   
    The extra_attributes in
    openssl_csr_new() sets the CSR
    attributes instead of subject DN, which incorrectly done previously.
   
    The dn in
    openssl_csr_new() allows setting an array
    of values for a single entry.
   
    New serial_hex added to
    openssl_csr_sign() to allow setting serial numbers
    in the hexadecimal format.
   
    Parsing ASN.1 UTCTime with openssl_x509_parse()
    fails if seconds are omitted for OpenSSL version below 3.2
    (-1 is returned for such fields).
    OpenSSL version above 3.3 did not load such certificates already.
   
    It is now possible to fetch the value of the
    PDO::ATTR_STRINGIFY_FETCHES attribute with
    PDO::getAttribute().
   
    A new PDO::PGSQL_ATTR_RESULT_MEMORY_SIZE
    has been added to retrieve the memory usage of query results with
    PDO::getAttribute() for drivers that support it.
   
    It is now possible to fetch the value of the
    
    FB_ATTR_DATE_FORMAT,
    FB_ATTR_TIME_FORMAT,
    FB_ATTR_TIMESTAMP_FORMAT,
    attributes with
    
    PDO::getAttribute().
   
Added new attributes to specify transaction isolation level and access mode. Five constants relating to this functionality have been added:
Pdo\Firebird::TRANSACTION_ISOLATION_LEVELPdo\Firebird::READ_COMMITTEDPdo\Firebird::REPEATABLE_READPdo\Firebird::SERIALIZABLEPdo\Firebird::WRITABLE_TRANSACTIONWhen using persistent connections, there is now a liveliness check in the constructor.
    The content that is built changes depending on the value of
    FB_API_VER in
    ibase.h.
    A new static method Pdo\Firebird::getApiVersion()
    can be used to obtain this information.
    This information is also now referenced in phpinfo().
   
    Five new data types are now available:
    INT128, DEC16, DEC34, TIMESTAMP_TZ, TIME_TZ
    .
    These are available starting with Firebird 4.0.
   
    It is now possible to fetch the value of the
    PDO::ATTR_FETCH_TABLE_NAMES attribute with
    
    PDO::getAttribute().
   
    Support retrieving the memory usage of queries for
    PDO::PGSQL_ATTR_RESULT_MEMORY_SIZE.
   
    If the column is of type FLOAT4OID or
    FLOAT8OID the value will now be returned as a
    float instead of a string.
   
    The conditions parameter of
    pg_select() is now optional and accepts an empty array.
   
The Phar::setAlias(), Phar::setDefaultStub() methods now have a tentative return type of true instead of bool.
posix_isatty() now sets the error number when the file descriptor/stream argument is invalid.
ReflectionGenerator::getFunction() may now be called after the generator finished executing.
    The backlog parameter of
    socket_create_listen() now has a default value of
    SOMAXCONN.
    Previously, it was 128.
   
The sodium_crypto_aead_aes256gcm_()* functions are now available on aarch64 CPUs with the ARM cryptographic extensions.
The SplPriorityQueue::insert(), SplPriorityQueue::recoverFromCorruption(), SplHeap::insert(), SplHeap::recoverFromCorruption() methods now have a tentative return type of true instead of bool.
SplObjectStorage now implements SeekableIterator.
    The default 'cost' value for the PASSWORD_BCRYPT
    hashing algorithm for password_hash() has been increased from
    10 to 12.
    
   
debug_zval_dump() now indicates whether an array is packed.
    long2ip() now has a return type of string
    
    instead of string|false.
   
    
    highlight_string() now has a return type of
    string|true instead of string|bool.
   
    
    print_r() now has a return type of
    string|true instead of string|bool.
   
     The mode parameter of the
     round() function has been widened to
     
     RoundingMode|int,
     
     accepting instances of a new RoundingMode enum.
     
    
Four new modes have been added to the round() function: RoundingMode::PositiveInfinity, RoundingMode::NegativeInfinity, RoundingMode::TowardsZero, RoundingMode::AwayFromZero
     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.
    
     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.
    
     The maximum precision that can be handled by round()
     has been extended by one digit.
     For example, round(4503599627370495.5) returned in
     4503599627370495.5,
     but now returns 4503599627370496.
    
The minimum libcurl version required is now 7.61.0.
    The CURLOPT_DNS_USE_GLOBAL_CACHE option no longer
    has any effect, and is silently ignored.
    This underlying feature was deprecated in libcurl 7.11.1,
    and removed in libcurl 7.62.0.
   
    Casting a GMP object to bool is now
    possible instead of emitting a E_RECOVERABLE_ERROR.
    The casting behaviour is overloaded such that a GMP
    object representing the value 0 is cast to false.
   
The minimum libxml2 version required is now 2.9.4.
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.
Unicode data tables have been updated to Unicode 16.0.
Support for the new VECTOR data type from MySQL 9.
The minimum OpenSSL version required is now 1.1.1.
The minimum libpq version required is now 10.0.
The minimum libpq version required is now 10.0.
Out of bounds accesses in SplFixedArray now throw exceptions of type OutOfBoundsException instead of RuntimeException. Because OutOfBoundsException is a child class of RuntimeException no behavioural changes are exhibited when attempting to catch those exceptions.
The typed properties XSLTProcessor::$cloneDocument and XSLTProcessor::$doXInclude are now declared.
The minimum zlib version required is now 1.2.11.
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(), or serialize().
    sprintf() using only %s and
    %d specifiers will be compiled into the equivalent
    string interpolation, avoiding the overhead of a function call and
    repeatedly parsing the format string.
   
Improved performance of number conversions and operations.
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.
Reduced memory usage of node classes.
Improved the performance of FTP uploads up to a factor of 10x for large uploads.
Added SSE2 and SHA-NI implementations of SHA-256. This improves the performance on supported CPUs by ~1.3x (SSE2), and 3x - 5x (SHA-NI). Credit to Colin Percival / Tarsnap for this optimization.
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.
Improved the performance of MySQLnd quoting.
Improved the performance of named capture groups.
Improved the performance of Random\Randomizer, with a specific focus on the Random\Randomizer::getBytes(), and Random\Randomizer::getBytesFromString() methods.
Improved performance and reduce memory consumption of XML serialization.
The performance of strspn() and strcspn() is greatly improved. They now run in linear time instead of being bounded by quadratic time.
Improved the performance of strpbrk().
get_browser() is much faster now, up to 1.5x - 2.5x for some test cases.
